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Full text of "Cork insulation; a complete illustrated textbook on cork insulation--the origin of cork and history of its use for insulation--the study of heat and determination of the heat conductivity of various materials--complete specifications and directions for the proper application of cork insulation in ice and cold storage plants and other refrigeration installations--the insulation of household refrigerators, ice cream cabinets and soda fountains"

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MOA'ARCII   OF  THE   CORK    lORI-ST 


Cork  Insulation 


A   COMPLETE   ILLUSTRATED   TEXTBOOK   OX    CORK   IXSULATIOX— THE 
ORKHX    OF   CORK   AXD   HISTORY    OF    ITS   USE  FOR    IXSULATION- 
THE  STUDY  OF  HEAT  AXD  DETERMIXATIOX  OF  THE  HEAT  COX- 
DUCTIVITY   OF   VARIOUS   MATERIALS— COMPLETE   SPECIFI- 
CATIOXS  AXD  DIRECTIOXS  FOR  THE  PROPER  APPLICA- 
TIOX     OF     CORK    IXSULATIOX    IX    ICE    AXD    COLD 
STORAGE    PLANTS   AND    OTHER   REFRIGERATION 
IXSTALLATIOXS— THE  IXSULATIOX  OF  HOUSE- 
HOLD      REFRIGERATORS,       ICE      CREAM 
CABIXETS    AXD    SODA    FOUXTAIXS. 


PEARL  EDWIN  THOMAS 

Engineering     Graduate,     1909,     The     Pennsylvania     State     College 
Identified   with   the   Cork   and    Insulati.jn   Industries   since    1912 


publishers 
Ntckekson  &  Collins  Co. 

CHICAGO 


-7" 


I 


Copyright,    1928,    by    the 

NICKERSON  &  COLLINS  CO. 

All   rights   reserved 

PRINTED     IN     THE     UNITED    STATES     OF     AMERICA 


PRESS  or 
ICE   AND    KKIRIGKKATKJN 

CHICAGO    -NKW     YORK 


To 

the  Memory  of 
JAMES  EDWARD  QUIGLEY 


184-^4- 


PREFACE 

In  submitting  this  first  complete  treatise  on  the  sources, 
harvesting,  manufacture,  distribution  and  uses  of  cork  and 
cork  insulation  products,  the  author  believes  that  he  has 
succeeded  in  adding  to  scientific  literature  a  work  for  which 
there  is  at  this  period  a  real  necessity  and  a  genuine  demand. 

The  collection  of  data  on  which  tlie  matter  herein  pub- 
lished is  based  has  necessitated  many  years  of  careful  re- 
search in  a  field  widely  scattered  and  rcc^uiring  thought  and 
discriminating  care  in  the  separation  of  the  grain  from  the 
chafif  in  published  matter  sometimes  of  a  more  or  less  dissolute 
nature  and  frequently  of  an  unreliable  character.  Such  matter  as 
is  here  presented  can  be  considered  authentic  and  authoritative 
and  relied  upon  unreservedly. 

When  consideration  is  given  to  the  fact  that  in  the  half 
century  just  passed  the  cork  industry  has  developed  and 
progressed  from  a  mere  matter  of  production  of  bottle 
stoppers  to  a  diversified  line  of  products  covering  hundreds  of 
separate  items  and  involving  cork  imports  valued  at  millions 
of  dollars  per  annum,  some  conception  of  the  magnitude  and 
importance  of  the  cork  industry  of  the  world  can  be  formed. 

For  the  architect,  engineer,  consulting  expert,  equipment 
designer,  car  and  steamship  builder,  plant  owner,  industrial 
manager,  and  for  every  one  interested  in  any  way  in  refriger- 
ation, ice  making,  cold  storage,  the  operation  of  markets, 
dairies,  creameries,  ice  cream  plants,  the  manufacture  of  house- 
hold and  commercial  refrigerators,  insulating  against  both 
heat  and  cold,  sound-proofing,  moisture-proofing,  humidity 
and  temperature  control,  this  book  will  be  found  indis- 
pensable. 

The  rapid  strides  of  the  development  of  the  cork  industry 
in  this  country  have  astonished  even  those  who  have  been 
and  are  now  directly  associated  with  the  cork  business,  and 
it  is  appreciated  that  as  yet  the  possibilities  of  future  applica- 


tion  of  cork  to  other  and  more  remote  industrial   purposes 
have  scarcely  been  touched. 

While  the  main  idea  sought  to  be  brought  out  em- 
phatically in  this  work  is  that  of  insulation,  it  is  thought  pos- 
sible that  the  subjects  covered  herein  may  lead  to  further  im- 
portant developments  and  progress  in  the  industry. 

In  addition  to  the  direct  credit  given  in  the  body  of  the  text, 
and  in  foot-notes,  grateful  acknowledgement  is  also  made  to  the 
following  individuals  and  concerns  whose  courtesy  and  coopera- 
tion made  possible  many  of  the  very  valuable  illustrations  con- 
tained in  this  work,  as  follows:  Armstrong  Cork  &  Insulation 
Co.,  United  Cork  Companies,  Cork  Import  Corporation,  Spanish 
Cork  Insulation  Co.,  John  R.  Livezey,  Edward  J.  Ward,  Rhine- 
lander  Refrigerator  Co.,  Leonard  Refrigerator  Co.,  Gifford- 
Wood  Co.,  and  the  American  Society  of  Refrigerating  Engineers. 

P.  EDWIN  THOMAS. 
Chicago,  July,  1928. 


TABLE  OF  CONTENTS. 

Part  I.— The  Cork  Industry. 
CHAPTER  I. 


The  Origin  of  Cork. 


1.  Early  Uses  of  Cork — 2.  Beginning  or'  the  Cork  Indus- 
try— 3.  Source  of  Supply — 4.  Home  of  the  Industry — 5. 
Characteristics  of  the  Cork  Oak. 


CHAPTER  II. 
Cork    Stripping 10 

6.  Removing  the  Outer  Bark — 7.  Virgin  Cork — 8.  Sec- 
ondary Bark — 9.    Boiling  and  Baling. 

CHAPTER  HI. 
Uses  of  Corkwood  and  Utilization  of  Cork  Waste.  ...        16 

10.  Hand  Cut  Corks— 11.  Other  Uses— 12.  Importance 
of  Sorting — 13.  Cork  Stoppers — 14.  Cork  Discs — 15.  Arti- 
ficial Cork — 16.    Cork  Insulation. 


CHAPTER  IV. 
Early  Forms  of  Cork  Insulation 25 

17.  Natural  Cork  and  Composition  Cork — 18.  Impreg- 
nated Corkboard. 

CHAPTER   V. 

Discovery  of  Smith's  Consolidated  Cork,  and  the  First 
Pure   Cork   Insulation 29 

19.  Smith's  Discovery — 20.  Cork  Covering  for  Steam 
Pipes — 21.  Cork  Covering  for  Cold  Pipes — 22.  Pure  Cork- 
board. 


viii  TABLE  OF  CONTENTS 

CHAPTER  VI. 

F.XTENT    OF   THE    CoRK    INDUSTRY 


23.  Is  Source  of  Supply  Adequate ?-24.  Cork  Stopper 
Industry— 25.  Cork  a  National  Necessity— 26.  Effects  of 
U.  S.  Tarifif  Act  of  1913—27.  Effect  of  the  World  War— 
28.  Recovery  of  the  Industry— 29.  Changing  Demands— 30. 
Tables  of  U.  S.  Imports    (1892-1924). 


Part  II.— The  Study  of  Heat. 
CHAPTER  VII. 

Heat,  Temperature  and  Thermal  Expansion 

31.  Molecular  Theory  of  Heat— 32.  Temperature— 33. 
Dissipation  of  Energy-34.  Effects  of  Heat-35.  Ther- 
mometers—36.  Air  Thermometer— 37.  Expansion  and  Con- 
traction—38.  Force  of  Expansion  and  Contraction— 39.  Ap- 
plications of  Exiiansion  and  Contraction— 40.  Coefficient  of 
Expansion— 41.  Determination  of  the  Expansion  of  Sub- 
stances. 

CHAPTER  VIII. 
Measurement  of  He.\t,  Change  of  State  and  Humidity 
42.  First  Law  of  Thermodynamics— 43.  Methods  of  Heat 
Measurement— 44.  Units  of  Heat— 45.  Thermal  Capacity  of 
a  Substance— 46.  Specific  Heat— 47.  Heat  of  Combustion— 
48.  Change  of  State  with  Rise  of  Temperature— 49.  The 
Melting  Point— SO.  Heat  of  Fusion— 51.  The  Boiling  Point— 
52.  Vaporization— S3.  Heat  of  Vaporization— 54.  Super- 
heating and  Undercooling  of  Liquids— 55.  Critical  Temper- 
atures—56.  Saturated  Vapor— 57.  Effect  of  Pressure  on 
Melting  Point— 58.  Effect  of  Pressure  on  Boiling  Point— 
59.  Boiling  and  Melting  Points  of  Mixtures— 60.  Cold  by 
Evaporation— 61.  Condensation  and  Distillation— 62.  The 
Dew  Point— 63.    Humidity. 

CHAPTER   IX. 

Transfer  of  Heat 

64.    Heat  Transference- 65.    Conduction— 66.    Convection— 


33 


67      Radiation-68.     Flow  of  Heat-69.     Total  Heat  Tran,^ 
■ei— 70.  Air  Spaces-71.  Heat  Transfer  by  Conduction  Only- 


11.    Heat   Loss  Through   Insulation. 


TABLE  OF  CONTENTS  ix 

CHAPTER  X. 

Determination  of  tpie  Heat  Conductivity  of  Various 
Materials    115 

7Z.  Methods  Emi.I.)ycd^74.  The  Ice-Box  Method— 75. 
The  Oil-Box  Method— 76.  The  Hot-Air-Box  Method— 77. 
The  Cold-Air-Box  Method— 78.  The  Hot-Plate  Method— 79. 
Tests  hy  Various  Authorities  on  Many  Materials. 


Part  III. — The  Insulation  of  Ice  and  Cold  Storage  Plants  and 
Cold  Rooms  in   General. 

CK AFTER  XI. 

Requirements  of  a  Satisf.xctok^'  Insulation  for  Cold 
Storage    Temperatures 167 

80.  Essential  Requirements — 81.  .\  Good  Nonconductor  of 
Heat — 82.  Inherently  Nona]>sorbent  of  Moisture — 83.  Sanitary 
and  Odorless — 84.  Compact  and  Structural!}-  Strong — 85.  Con- 
venient in  Form  and  Fas\  to  Install — 86.  A  Fire  Retardant — 
S7.  Easily  Ohiaincd  and  Reasonable  in  Cost — 88.  Permanent 
Insulating   Effijienc\'. 


CHAPTl-.R  XII. 

Pi^oi'ER  Thickness  of  Corkcoakd  to  Use  a.md  Structural 

'    SUG(JESTI0NS    178 

89.  Economic  Value  of  Insulating  Materials — 90.  Ten- 
dency Toward  More  and  Better  Insulation — 91.  Proper 
Thickness  of  Corkboard  to  Use — 92.  Importance  of  Proper 
Insulation  Design — 93.  Types  and  Design  of  Cold  Storage 
Rooms — 94.  Types  of  Bunkers  and  Details  of  Construction — 
95.  Circulation,  Ventilation  and  Humidification — 96.  Prepa- 
ration of  Building  Surfaces  to  Receive  Insulation — 97.  In- 
sulation of  Floors,  Columns,  Ceilings  and  Beams — 98.  Doors 
and  Windows — 99.  Interior  Finishes  for  Cold  Storage 
Rooms — 100.  Asphalt  Cement  and  Asphalt  Primer — 101. 
Emulsified  Asphalt. 


240 


X  TABLE  OF  CONTENTS 

CHAPTER  XIII. 

Complete  Specifications   for  the  Erection   of  Cork- 
board    

102.  Scope  and  Purpose  of  Specifications — 103.  Walls : 
Stone,  Concrete  or  Brick— 104.  Walls:  Wood— 105. 
Ceilings:  Concrete— 106.  Ceilings:  Wood— 107.  Ceilings: 
Self-Supported— 108.  Roofs  :  Concrete  or  Wood— 109.  Floors  : 
Wood — 110.  Floors:  Concrete — 111.  Partitions:  Stone,  Con- 
crete or  Brick — 112.  Partitions:  Wood — 113.  Partitions:  Solid 
Cork — 114.  Tanks:  Freezing — 115.  Finish:  Walls  and  Ceil- 
ing— 116.    Finish:    Floors — 117.    Miscellaneous  Specifications. 


CHAPTER  XIV. 

Complete  Directions   for  the   Proper  Applicaton   of 
Corkboard  Insulation 279 

118.  General  Instructions  and  Equipment — 119.  First  Layer 
Corkboard,  against  Masonry  Walls,  in  Portland  Cement 
Mortar — 120.  First  Layer  Corkboard,  against  Masonry  Walls, 
in  Asphalt  Cement — 121.  First  Layer  Corkboard,  against 
Wood  Walls,  in  Asphalt  Cement — 122.  Second  Layer  Cork- 
board,  against  First  Layer  on  Walls,  in  Portland  Cement 
Mortar— 123.  Second  Layer  Corkboard,  against  First  Layer 
on  Walls,  in  Asphalt  Cement — 124.  First  Layer  Corkboard,  to 
Concrete  Ceiling,  in  Portland  Cement  Mortar — 125.  First 
Layer  Corkboard,  in  Concrete  Ceiling  Forms — 126.  First 
Layer  Corkboard,  to  Wood  Ceiling,  in  Asphalt  Cement — 
127.  Second  Layer  Corkboard,  to  First  Layer  on  Ceiling, 
in  Portland  Cement  Mortar — 128.  Second  Layer  Corkboard, 
to  First  Layer  on  Ceiling,  in  Asphalt  Cement — 129.  Double 
Layer  Corkboard,  Self-Supporting  T-Iron  Ceiling,  Portland 
Cement  Mortar  Core — 130.  First  Layer  Corkboard,  over  Con- 
crete or  Wood  Floor  or  Roof,  in  Asphalt  Cement — 131. 
Second  Layer  Corkl)oard,  over  First  Layer  on  Floor  or 
Roof,  in  Asphalt  Cement^l32.  Single  Layer  Corkboard,  be- 
tween Partition  Studs  with  Joints  Sealed  in  Asphalt  Ce- 
ment— 133.  First  Layer  Corkboard,  Self-Supporting  Partition, 
Joints  Sealed  in  Asphalt  Cement — 134.  Second  Layer  Cork- 
board,  against  First  Layer  of  Self-Supporting  Partition,  in 
Portland  Cement  Mortar — 135.  Second  Layer  Corkboard, 
against  First  Layer  of  Self-Supporting  Partition,  in  Asphalt 
Cement — 136.  Double  Layer  Corkboard,  Freezing  Tank  Bot- 
tom, in  Asphalt  Cement — 137.  Regranulated  Cork  Fill,  Freez- 
ing Tank  Sides  and  Ends,  with  Retaining  Walls — 138.  Single 
Layer  Corkboard  and  Regranulated  Cork  Fill,  Freezing  Tank 


TABLE  OF  CONTENTS 

CHAPTER  XIV— Continued. 

Sides  and  Ends- — 139.  Double  Layer  Corkboard,  Freezing 
Tank  Sides  and  Ends — 140.  Portland  Cement  Plaster — 141. 
Factory  Ironed-On  Mastic  Finish— 142.  Emulsified  Asphalt 
Plastic — 143.  Concrete  Wearing  Floors — 144.  Wood  Floors 
Secured  to  Sleepers  Imbedded  in  Insulation — 145.  Galvanized 
Metal   over  Corkboard. 


Part    IV. — The   Insulation   of   Household    Refrigerators,    Ice 
Cream  Cabinets  and  Soda  Fountains. 


CHAPTER  XV. 

History  of  Refrigeratox  Employed  to  Preserve  Food- 
stuffs         317 

146.  Early  Uses  of  Refrigeration — 147.  The  Formation, 
Harvesting  and  Storing  of  Natural  Ice — 148.  The  Develop- 
ment of  the  Ice  Machine — 149.  Early  Methods  of  Utilizing 
Ice  as  a  Refrigerant — ISO.  Early  'Methods  of  Insulating  Cold 
Stores. 

CHAPTER  XVI. 

Development  of  the  Corkboard  Insulated  Household 
Refrigerator    332 

151.  Early  Forms  of  Household  Coolers — 152.  The  House- 
hold Ice-Box — 153.  The  Era  of  Multiple  Insulation  in  House- 
hold Refrigerators — 154.  The  Advent  of  the  Household  Re- 
frigerating Machine  and  Early  Trials  with  Pure  Corkboard 
in  Household  Refrigerators — 155.  The  Modern  Corkboard 
Insulated  Household  Refrigerator — 156.  Typical  Details  of 
Household  Refrigerator  Construction — 157.  Notes  on  the 
Testing  of  Household  Refrigerators. 


CHAPTER  XVII. 

Development  of  the  Corkboard  Insulated  Ice  Cream 
Cabinet   386 

158.  Growth  of  the  Ice  Cream  Industry — 159.  Ice  and  Salt 
Cabinets — 160.  Mechnical  Ice  Cream  Cabinets — 161.  Typical 
Details  of  Ice  Cream  Cabinet  Construction — 162.  Notes  on 
How  to  Test  Ice  Cream  Cabinets. 


xii  TABLE  OF  CONTENTS 

CHAPTER  XVIII. 
The  Refrigerated  Soda  Fountain 403 

163.  Automatic  Operation  of  an  Intricate  Unit  Made  Pos- 
sible with  Corkboard  Insulation — 164.  Extracts  from  Manu- 
facturers' Specifications  for  Modern  Mechanically  Refriger- 
ated Soda  Fountains  with  Typical  Details  of  Construction. 

Appendix     425 

Refrigeration  in  Transit — The  Ability  of  Refrigerator  Cars 
to  Carry  Perishable  Prockicts — Tlie  Utvelopment  of  the 
Standard  Refrigerator  Car — Specifications  for  Refrigerator 
Car  Insulation — Cork  Paint — Pulverized  Cork — Subirine— 
Cork  as  a  Building  Material — Some  Uses  of  Corkboard  In- 
sulation— Relative  Humidity  Table — Heat  Transmission  :  A 
National  Research  Council  Project — Air  Infiltration — Cork 
Dipping  Pan — Protection  of  Insulation  Against  Moisture — 
How  Insulation  Saved  a  Refinery — Economy  of  Gasoline 
Storage  Tank  Insulation — Interior  Finish  of  Cold  Storage 
Rooms  in  Hotels — Concrete — Example  of  Purchaser's  Insula- 
tion Specifications — Freight  Classifications,  Class  Rates,  Etc. — 
Pure  Corkboard  and  Sundries — Freight  Classifications,  Class 
Rates,  Etc. —  Cork  Pipe  Covering,  Cork  Lags,  Cork  Discs  and 
Sundries — ^Cork  Pipe  Covering  Specifications — Instructions 
for  Proper  Application  of  Cork  Pipe  Covering — A  Good 
Drink  of  Water — Fundamental  Contract  Law — Engineering 
Contracts. 

Topical  Index   523 


CORK  INSULATION 

Part  I — The  Cork  Industry. 


CHAPTER  I. 

THE  ORIGIN  OF  CORK. 

1. — Early  Uses  of  Cork. — The  story  of  cork  is  so  little 
known  and  shrouded  with  so  much  mystery  that  the  world 
has  never  had  a  complete  and  comprehensive  account  of  iU 
The  utility  and  general  uses  of  the  "cork  of  commerce,"  as 
well  as  its  native  land,  are  no  longer  a  part  of  the  mysticism ; 
but  its  character,  composition  and  chemical  construction  are 
still  the  subject  of  research  and  experimentation. 

'The  uses  of  the  outer  bark  of  the  cork  oak  tree  have  been 
traced  far  back  into  a  dim  past,  but  for  our  purpose  it  will  be 
cnousjh  to  go  back  no  further  than  the  first  century  of  the 
Christian  era.  The  elder  Pliny  wrote  al:)()ut  the  cork  oak  tree 
then,  in  his  work  on  natural  histor}-.  and  recognized  twenty 
centuries  ago  at  least  four  of  the  principal  functions  that  cork 
fills  in  the  world  today,  which  involved  a  recognition  of  the 
two  principal  properties  of  cork  bark  that  make  its  use  of  so 
much  value  as  a  commercial  insulating  material — its  marked 
ability  to  retard  the  flow  of  heat  and  its  freedom  from  capil- 
larity.    These  two  properties,  in  combination,  were  provided 

•by  Nature  to  make  this  interesting  and  remarkable  material 
the  foundation,  when  put  through  proper  manufacturing 
processes,  for  the  best  cold  storage  and  refrigerator  insulation 
yet  known  to  mankincL 

**  As  is  often  the  case  with  many  important  discoveries,  the 
first  use  of  cork  probably  came  through  accident ;  for  its  em- 

I  ployment  "attached  as  a  buoy  to  the  ropes  of  ships'  anchors 
and  the  drag-nets  of  hshermen"  suggests  that  a  piece  of  cork 
bark  found  its  way  to  the  sea  where  its  unusual  buoyancy  was 
first  noted  and  utilized  bv  fishermen   and  sea-faring  men   as 


2  CORK  INSULATION 

floats  for  nets,  buoys  for  anchors,  cork  jackets  for  life  pre- 
servers, and  later  as  plugs  for  vintage  casks  sealed  in  with 
pitch  and  as  winter  sandals  for  women.  ^ 

Since  Pliny  was  writing  history,  some  two  thousand  years 
ago,  it  is  safe  to  assume  that  the  very  first  use  ever  made  of 
cork  must  date  well  before  his  time,  perhaps  500  B.  C,  or 
1000  B.  C. — there  is  now  no  means  of  knowing. 


FIG.   1.— CORK  MOORING  AND  ANCHORAGE  BUOYS. 

2. — Beginning  of  the  Cork  Industry. — During  many  cen- 
turies of  the  Christian  era  the  great  cork  forests,  bordering 
the  Mediterranean  sea,  were  ravaged  by  wars  and  fires  and  the 
demand  for  timber  and  charcoal.  But  at  least  some  of  these 
sturdy  cork  oak  trees  managed  to  escape  and  later,  under 
kindlier  treatment,  sprpad  out  over  the  mountain  slopes  and 
gave  to  Spain,  Portugal  and  Algeria  one  of  their  chief  pres- 
ent sources  of  revenue — the  growing  of  "corkwood." 

'^  It  was  not  until  the  sixteenth  or  seventeenth  century,  how- 
ever, that  the  real  beginnings  of  the  great  cork  industry,  as 
it  is  known  today,  may  be  said  to  have  begun,  with  the  gen- 
eral introduction  of  the  glass  bottle.  Then  cork  bottle  stop- 
pers quickly  came  into  general  use,  being  elastic,  com- 
pressible, tasteless,  odorless,  and  impervious  to  water,  and 
gave  the  cork  industry  such  impetus  as  to  establish  it  upon 
a  sound  footing  for  all  time.'*' 


ORIGIN  OF  CORK  3 

3. — Source  of  Supply. — While  southern  France  and  Italy, 
including  the  isles  of  Corsica,  Sardinia  and  Sicily,  are  factors 
in  the  harvesting  and  supplying  of  the  crude  material,  yet 
Spain,  Portugal,  Algeria  and  Tunis  continue  to  supply  the 
world  with  the  bulk  of  the  raw  cork  that  is  consumed. 
Morocco,  in  north  and  northwest  Africa,  provides  an 
enormous  and  for  the  greater  part  an  undeveloped  area  of 
cork  forests*  but  this  field  is  now  being  opened  up  under 
careful  supervision,  and  should  grow  rapidly  in  importance 
as  a  source  of  suppl\-. 


FIG.    2.— CORK    1!( 


■!.E    STOrPERS. 


The  total  area  covered  by  cork  forests  in  all  countries  is 
estimated  at  from  four  to  five  million  acres,''^  and  the  annual 
yield  of  corkwood  in  1913  at  about  two  hundred  thousand 
tons.fl  The  shaded  areas  on  the  accompanying  map  repre- 
sent the  principal  places  in  the  world  where  the  cork  oak 
grows.  "Mt  flourishes  best  in  an  altitude  of  1,600  to  3,000  feet, 
in  an  average  mean  temperature  of  55°  F.,  and  the  Mediter- 
ranean basin  is  therefore  particularly  suitable  for  the  growing 
of  the  cork  oak  and  the  harvesting  of  its  outer  bark  of  qual- 
ity. < 


<• 


Armstrong  Cork  Company,  1909. 
tU.    S.   Tariff  Commission's   1924   Dictionary   of  Tariff  Information. 


k 


CORK   INSULATION 


vfany  attem])ts  lia\c  l_)een  made  to  transplant  tliis  interest- 
ing tree,  Imt  the  result  of  e\ery  sueh  effort  has  been  futile. 
Just  before  t'n.e  Ci\il  war,  in  1859',  the  United  States  Govern- 
ment provided  funds  to  brin;;-  I'ortuijLse  cork  acorns  to  se\'- 
cral  of  the  Southern  States  for  planting;  but  after  a  dozen 
years  c^r  so  it  was  concluded,  in  spite  of  the  neglect  of  the 
seedlings  occasioned  by  the  War  of  tlie  Rebellion,  that  the 
experiment  was  not  a  commercial  success.  Some  of  these 
cork  oak  trees  are  still  standing  in  Mississippi  and  Georgia, 
but  the  outer  bark  never  matured  satisfactorilw^   "^^ 


FIC.    3— S()UK(  E   OK    IHK    WORLDS    Sl'PPLY    OF    CORK. 

*In  1872  another  eft'ort  was  made  to  grow  the  cork  oak  in 
southern  California.  Init  the  outcome  pro\ed  no  better  there 
than  it  did  at  an  earlier  date  in  the  luist.*Four  of  these  trees 
are  now  standing  in  the  Methodist  churchyard  at  Fourth  and 
Arizona  Streets.  Santa  Monica.  California,  and  a  half  dozen 
more  have  recently  been  located  by  H.  H.  Wetzel  in  Santa 
Monica  canyon;  ])ut  while  the  trees  themselves  have  flour- 
ished, the  quality  of  their  salient  ])roduct  is  inferior  and  of  no 
commercial  value.  ^ 


ORIGIN  OF  CORK 


FIG.    4.— CORK    OAK    TRKE    GROWING    IN    SANTA    MONICA,    CALIF. 


6  CORK  INSULATION 

•^  4. — Home  of  the  Industry, — The  ancient  Spanish  province 
of  Catalonia,  in  the  northeast  or  Barcelona  area,  has  long  been 
recognized  as  the  greatest  cork  manufacturing  district  in  the 
world,  the  towns  of  Palamos,  Palafrugell,  San  Feliu  de 
Guixols,  Bisbal,  Figueras  and  others  being  devoted  almost 
exclusively  to  cork  and  cork  products.  Domestic  cork  fac- 
tories are  scattered  throughout  the  cork  areas  of  Spain  and 
Portugal,  to  the  extent  of  i)erhaps  a  thousand  different  estab- 


FIG.    S.— LOADING    CORKWOOD    FOR    EXPORT    AT    PORT    OF    PALAMOS, 
SPAIN. 


lishments,  while  the  remainder  of  the  yield,  in  the  form  of 
baled  corkwood,  cork  waste,  shavings  and  cork  refuse  of  all 
kinds,  is  exported  to  Sweden,  Denmark,  Russia,  Austria,  Ger- 
many, France,  Great  Britain  and  the  United  States,  the  last 
four  named  ordinarily  absorbing  perhaps  eighty-five  per  cent 
of  the  total  product  of  the  producing  countries,  to  be  worked 
into  hundreds  of  different  cork  articles  of  trade.  ^ 

\JBecause    most    people    think    of    Spain    as    an    easy-going 
country  of  medieval  ways,  with  no  great  wealth  or  material 


ORIGIN  OF  CORK  7 

development,  it  can  not  be  amiss  to  say  a  word  about  Bar- 
celona, the  capital,  so  to  speak,  of  the  cork  industry,  and 
which  jnust  be  ranked  today  amoAg  the  great  cities  of  the 
world.  ^*The  Barce^kma  distnpt-'(5r  Spain  would  be  an  amazing 
surprise  to  any  one  mip^ilTg  to  it  with  no  better  idea  of  what 
to  expect.  Barc^krfia  is  tddaj,:,jm  enormous  city  of  nearly  a 
million  pomil^tion,  extending  from  the  sea  toTHe^fDDthills  of 
the_Byr€mies,  filling  the  plain  in  between  and  stretching  out 
into  the  valleys  and  well  along  the  coast. 

From  a  point  on  Tibidabo  some  1,500  feet  above  the 
Mediterranean  sea,  can  be  seen  an  immense  metropolis  spread 
out  with  the  exact  regularity  of  any  of  our  modern  cities  of 
the  Middle  West.  Ofif  to  one  side  a  splotch  by  the  harbor 
faintly  marks  the  old  Barcelona  of  crooked,  narrow  streets, 
but  even  this  is  fast  giving  way  to  make  room  for  new,  wide 
thoroughfares  that  link  modern  highway  and  transportation 
lines. 

Modern  office  and  public  buildings,  hotels  and  shops,  flats 
and  apartments,  broad  avenues  and  boulevards  lined  with 
trees  and  completely  equipped  with  excellent  electric  tram 
and  omnibus  service,  athletic  stadiums  and  open  air  theatres, 
palatial  villas  and  residences,  electric  trains  every  few  minutes 
from  the  heart  of  the  city  out  into  the  country,  a  subway  under 
construction,  at  night  the  central  squares  lit  up  with  flashing 
Broadway  sky  signs — there  is  little  indeed  to  suggest  the 
Spain  of  our  fancy. 

Barcelona  began  to  grow  after  the  International  Exposi- 
tion of  1888,  when  new  capital  gave  an  immense  impetus  to 
its  many  industries;  and  while  it  is  the  chief  seaport  of  Spain, 
it  is  as  a  manufacturing  center  that  it  has  risen  to  the  position 
of  one  of  the  great  cities  of  the  world. 

^5. — Characteristics  of  the  Cork  Oak. — The  botanical  name 
for  the  cork  oak  is  Quercus  suher.  "It  grows  and  develops  in 
ground  of  little  depth,  and  often  quite  stony,  being  seldom 
found  in  calcareous  soil,  preferring  a  sandy  soil  of  felspar."* 
It  ordinarily  attains  a  height  of  from  twenty-five  to  fifty  feet, 
but  occasionally  grows  to  a  height  of  more  than  one  hundrec 


'Consul  Schenck's  Report,   1890. 


8  CORK   INSULATION 

and  fifty  feet  and  to  a  diameter  of  as  mueh  as  four  feet.f 
Its  branches  usuall}-  are  full-spread  and  are  co\  ered  with  small 
evergreen  leaves  ha\ing"  a  veUety  feel  and  a  glossy  appear- 
ance. Its  roots  spread  considerably  and  attain  much 
strength,  often  being  xisible  abo\e  ground. 

During-  April  and  Ala}  the  }ellowish  blossoms  appear, 
which  are  followed  by  the  acorns  that  ripen  and  at  once  fall  to 
the  ground  during  the  last  four  months  of  the  year.  These 
acorns  are  bitter  to  the  taste,  but  gi\e  a  ])eculiarly  piquant 
flavor  to   SiJanish   mountain   hams   when   ted   to   swine.     The 


cork  oak  offers  but  little  shade,  which  permits  the  soil  to  be- 
come very  dry  and  of  inferior  producing  value  unless  the 
young  trees  are  growii  close  together  until  they  are  about 
twenty-hve  xcars  olds/  Jf  the  soil  is  [xjor,  the  outer  bark  is 
thin  but  of  fine  texture;  if  the  soil  is  rich,  the  bark  is  thick, 
spongy  and  inclined  to  be  coarse.  These  characteristics  are 
carefully  studied  from  an  agricultural  standpoint,  in  the 
\-arious  cork  growing  districts,  and  are  dealt  with  as  reason 
dictates. 

The  outer  bark  of  the  cork  oak  consists  of  thin-walled  cells 
filled  with  air,  is  destitute  of  intercellular  spaces,  and  is  im- 
permeable to  air  and  water.     These  cells  are   so  small   that 


tHcnry   Vincke,    1925. 


ORIGIN  OF  CORK  9 

they  can  be  ^■isllalize(l  only  with  a  high  powered  microscope, 
there  being  about  four  hundred  milHon  per  cubic  inch,  but 
each  cell  contains  a  microscopic  bit  of  air  and  is  sealed  against 
all  other  cells  so  that  the  entrapped  air  can  not  move  about 
within  the  material.  It  is  this  peculiar  structure  of  cork  bark 
that  makes  it  an  excellent  nonconductor  of  heat  and,  at  the 
same  time,  impervious  to  air  and  water,  which  latter  property 
is  absolutely  essential  in  an  insulating  material  that  is  to  be 
employed  in  cold  storage  and  refrigerator  construction  w^here 
moisture  is  always  present.  *'A 


CHAPTER  II. 
CORK  STRIPPING. 

6. — Removing  the  Outer  Bark. — The  cork  of  commerce,  or 
corkwood,  is  the  outer  bark  of  the  cork  tree,  which  belongs  to 
the  oak  family  and  which  has  been  described.  This  outer 
bark  can  readily  be  removed  during  the  summer  months,  gen- 
erally during  July  and  August,  without  harm  to  the  tree, 
although  considerable  skill  is  required  if  injury  to  the  inner 
or  sap-carrying  bark  is  to  be  avoided.  French  strippers  some- 
times use  crescent-shaped  saws,  but  Spanish  strippers  in- 
variably use  a  long-handled  hatchet,  the  handle  tapered  at 
the  butt  in  the  shape  of  a  wedge. 

When  cork  oak  trees  attain  a  diameter  of  about  five  inches, 
or  measure  forty  centimeters  in  circumference  according  to 
the  Spanish  practice,  which  fixes  the  age  of  the  tree  at  about 
twenty  years,  the  virgin  outer  bark  is  removed.  It  is  cus- 
tomary to  cut  the  l)ark  clear  through  around  the  base  of  the 
tree  and  again  around  the  trunk  just  below  the  main  branches, 
the  two  incisions  then  being  connected  by  probably  two  ver- 
tical cuts.  By  using  the  long  handle  of  the  hatchet  as  a  wedge 
and  lever,  the  tree's  outer  bark  is  easily  pried  off.  The  lower 
portions  of  the  limbs  are  stripped  in  like  manner,  frequently 
yielding  a  liner  grade  of  corkwood  than  that  of  the  trunk. 
The  thickness  of  this  virgin  outer  bark  varies  from  about  one- 
half  to  two  and  one-half  inches,  while  the  yield  per  tree  also 
varies  from  a  half  hundred  to  several  hundred  pounds,  de- 
pending on  both  its  size  and  age  when  the  virgin  stripping  is 
accomplished. 

7. — Virgin  Cork. — This  virgin  cork  bark,  called  "borniza" 
in  Spain,  is  rough,  coarse  and  dense  in  texture.  It  is  there- 
fore of  limited  commercial  value,  except  as  used  by  florists 

10 


CORK  STRIPPING 


11 


and   others   for   decorative   purposes,   and,   when   ground,   as 
packing  for  grapes,  although  it  has  of  recent  years  come  into 


FIG.  7.— REMOVING  THE  OUTER  BARK  FROM  THE  CORK  (»AK 


use  also  in  the  manufacture  of  linoleum  and,  when  treated, 
in  the  manufacture  of  cork  insulation. 

So  long  as  the  inner  bark  or  skin  is  not  injured,  the  re- 
moval of  the  outer  bark  is  beneficial  rather  than  harmful  to 


12  CORK  INSULATION 

the  cork  oak  tree;  for  this  unscarred  inner  bark,  with  its  Hfe- 
giving  sap,  immediately  undertakes  the  formation  of  a  new 
covering  of  better  quality.  Each  year  this  inner  bark,  the 
tree's  real  skin,  forms  a  la\er  of  cells  within,  increasing  the 


FIG.  8.— VIRGIN   CORK  AND  SECOND   STRIPPING  BARK. 

diameter  of  the  trunk,  and  a  layer  of  cells  without,  adding 
thickness  to  the  covering  of  outer  bark.  If  the  inner  bark 
is  injured,  the  growth  of  the  outer  bark  is  permanently 
stopped  at  that  point,  the  injured  area  appearing  as  scarred 


FIG.    9.— CORK    BARK— "BACK"    AND    "BELLY". 

and  uncovered  for  the  remainder  of  the  life  of  the  tree.  Also, 
stripping  is  never  done  during  a  "sirocco," — a  hot  southernly 
wind  blowing  from  the  African  coast  to  Italy,  Sicily  and 
Spain, — which  would  dry  the  inner  bark  too  rapidly  and  ex- 
clude all  further  formation  of  outer  bark. 

8. — Secondary   Bark. — After  eight  or  ten  years  the  outer 
bark  is  again  removed,  known  as  "pelas"  or  secondary  bark. 


CORK  STRIPPING 


13 


and,  while  of  nnich  better  quality  than  the  virgin  bark,  it  is 
not  as  fine  in  texture  as  future  stripping?,  which  follow  every 
eight  or  ten  years  from  the  time  the  tree  is  about  forty  years 
of  age  until  it  is  a  hundred  or  more  years  old.  When  the 
cork  oak  has  been  stripped  about  live  times,  or  when  about 
ninetv  rears  old,  subsequent  strippings  yield  a  bark  that  is 
more  grain\-  and  of  less  \alue  for  tajjer  corks  and  cork  jiaper. 
The  second  and  all  subsec|uent  strippings  of  the  outer  bark  of 


"»-^ 


FIG.   10.— HANDLl.XU   C(-)KK\\  OOD  I.N    THE   FOREST. 

the  cork  oak  tree  is  known  a>  tlie  cork  of  commerce,  wliile 
the  term  "cork  waste"  is  employed  to  describe  the  residue 
from  the  cutting  of  natural  cork  articles,  and  also  the  forest 
waste  or  refuse  remaining  after  the  selection  of  the  commer- 
cial bark. 


9. — Boiling  and  Baling. — As  the  outer  bark  of  the  cork  oak 
is  remoNcd,  under  the  regulations  and  j)recautions  that  are 
prescribed  by  the  different  cork  growing  countries,  it  is  piled 
for  a  few  days  to  dry  out,  after  which  it  is  weighed,  removed 
to  the  boiling  station  and  there  stacked  for  a  few  weeks  of 


14 


CORK  INSULATION 


seasoning  preliminary  to  being  boiled.  The  outer  surface  of 
cork  bark  is  rough  and  woody  and  contains  considerable  grit, 
due  to  its  long  exposure  to  the  elements.  After  boiling,  this 
"hard-back,"  as  it  is  called,  is  readily  scraped  ofT;  but  since  the 
weight  is  thereby  reduced  about  twenty  per  cent,  and  cork- 
wood is  sold  by  weight,  it  is  the  tendency  to  want  to  slight 
this  operation.  The  same  boiling  process  removes  the  tannic 
acid,  increases  the  volume  and  the  elasticity  of  the  bark, 
renders  it  soft  and  pliable  and  flattens- it  out  for  baling  after 


pPHRT^^P^  ',"              vi""'' 

"Sjs-ij  ~~^'^*^5Si_3BAiii 

■  "^-        r 

-CORKWOOD   SORTING  AND 


first  being  sorted  as  to  quality  and  thickness.  Sometimes  the 
boiling  is  not  done  until  the  raw  cork  bark  comes  into  the  posses- 
sion of  those  in  Spain  or  Portugal  who  intend  to  utilize  it  in 
their  own  domestic  manufacturing  plants,  because  then  the 
complete  boiling  operation  can  be  carefully  supervised  and 
controlled.  However,  it  is  customary,  if  the  forest  is  distant, 
water  is  plentiful  and  the  quantity  of  bark  is  ample  to  justify 
the  equipment,  to  set  up  the  copper  vats  at  a  convenient  point 
and  carry  out  the  boiling  operation  right  in  the  forest. 

The  mountaneous  nature  of  the  country,  where  most  of  the 
cork  trees  abound,   makes  its  desirable   that   the   Spaniard's 


CORK  STRIPPING  15 

much  abused  friend,  the  faithful  burro,  be  employed  to  trans- 
port corkwood  to  domestic  factories,  or  to  the  railway  for 
freighting  to  the  seaport  warehouses  in  Spain  and  Portugal, 
the  city  of  Seville,  Spain,  being  probably  the  largest  deposi- 
tory of  corkwood  in  the  world. 

Before  exporting,  the  bales  are  opened,  the  edges  of  each 
piece  of  bark  are  trimmed  and  the  corkwood  is  again  sorted 
into  many  grades  of  thickness  and  quality.  This  final  sorting, 
before  re-baling  for  shipment,  is  done  by  experts  who  "know 
cork,"  because  the  successful  and  economical  manufacture  of 
cork  products  hinges  on  it.  The  large,  flat  pieces,  known  as 
planks  or  tables,  are  first  laid  in  the  baling  box  to  form  the 
bottom  and  sides  of  the  bale,  smaller  pieces  being  filled  in  the 
center  and  larger  pieces  used  again  to  cover  the  top.  Pressure 
is  then  applied  to  make  a  compact  mass,  which  steel  hoops 
bind  securely. 


CHAPTER  III. 

USES  OF  CORKWOOD  AND  UTILIZATION  OF  CORK 
WASTE. 

10. — Hand  Cut  Corks. — Soon  after  the  general  introduc- 
tion of  tlie  glass  bottle,  in  the  se\enteenth  century,  the  manu- 
facture of  cork  stoppers  consumed  the  bulk  of  the  corkwood 


FIG.    12.~.si'A.M.\RI)S    ('L-'rTT.\G    CORK    BY    HAND. 

that  was  harxested.  and  continued  to  do  so  for  several  cen- 
turies. The  manufacture  of  these  "corks"  was  orginally  done 
by  hand  in  the  producing  countries.  The  slabs  or  pieces  of 
cork  bark  were  sliced  to  a  width  equal  to  the  length  of  the 
stopper  desired,  and  these  strips  w^ere  then  cut  into  squares, 
or  "quarters,"  from  wdiich  the  corks  were  rounded  by  hand. 
The  greatest  skill  was  acquired  by  the  Cktalons,  who  today 
rank  as  the  most  adept  cork  workmen  in  the  world. 

The  manufacture  of  bottle  corks  by  hand  was  ne\er  carried 


USES  OF  CORKWOOD  AND  CORK  WASTE  17 

on  to  any  great  extent  in  the  United  States,  although  prior  to 
the  Civil  War  there  were  a  few  sucfi  establishments  in  Boston, 
New  York  and  Philadelphia.  In  Spain  and  Portugal,  how- 
ever, there  are  to  this  day  many  small  hand  cork  manufac- 
tories, although  machinery  is  used  by  the  large  and  more 
modern  plants.  While  Portugal  attained  rank  with  Spain  as 
a  cork  manufacturing  country,  it  has  since  come  to  export  a 
much- larger  proportion  of  its  corkwood  in  unmanufactured 
form  than  does  Spain.  Probably  three-fourths  of  the  cork- 
wood grown  in  Spain  is  consumed  in  Spain;  that  is,  is  manu- 
factured into  some  cork  product,  and  in  addition,  Spain  im- 
ports large  c^uantities  from  Portugal  and  Algeria.  Spain,  in  a 
word,  is  the  cork  clearing  house  of  the  world,  and  cork  is  one 
of  the  principal  industries,  if  not  ihe  principal  industry,  of  the 
Spanish  people. 

11. — Other   Uses. — In    addition    to   "straight''   and    "tai)er" 
corks,  al)out  whiJi  more  will  l)c  said  ])resently.  a  great  \ariety 


I  li;.     13.  — C'OKK     WASHERS     AND     (iASKETS— OXE     OF     MANY     USES     J'OI^ 
CORK. 

of  disks,  washers,  floats,  ]:)UO}S.  life  rings,  balls,  mats,  handle 
grips,  gaskets,  bobl^ers,  life  preservers,  as  well  as  shoe  insoles, 
polishing  disks,  cork  paper,  tropical  helmets,  rafts,  bungs, 
French  lieels  for  shoes,  bedding,  sound  isolation,  heat  and  cold 
insulation,  tioor  tiles,  roof  tiles,  sweat  IkukIs,  lining  for  hats, 
the  basis  for  ladies'  hat  and  dress  trimmings,  pulley  and 
clutch  inserts,  Spanish  black  for  i)aint.  cigarette  tips,  wadding 
for  gun  cartridges,  ])acking  for  glass  and  fruits,  bulletin 
boards,  the  basis  of  linoleum  manufacture,  an  important  in- 
gredient in  good  stucco  i)laster,  and  probably  a  hundred  or 
so  additional  items  of  imj^ortance  are  manufactured  from 
corkwood  and  cork  waste. 


rS  CORK  INSULATION 

12. — Importance  of  Sorting. — "In  taking  up  the  processes 
of  manipulation  we  naturally  start  from  the  beginning,  but 
the  beginning  in  this  case  has  a  peculiar  significance  as  relat- 
ing to  the  whole,  for  it  is  apparent  to  utilize  corkwood  to  the 
fullest  extent  its  qualities  must  be  studied  and  the  best  used 
first,  so  that  the  beginning  of  the  corkwood  industry  is  pecu- 
liar in  this  fact,  that  it  takes  the  best  part  and  leaves  but 
scrap,  which  must  be  studied  carefully  to  realize  the  value  lost 
in    the    first    process;    therefore,    in    the    manufacture    of   one 


FIG.    14.— CORKWOOD   STORAGE    YARD   AT   ALGECIRAS,    SPAIN. 

article  of  corkwood  it  is  necessary  to  make  provision  for  the 
scrap  (waste)  created,  and  this  is  a  characteristic  of  all  such 
(cork)  establishments."* 

The  bulkiness  of  corkwood  is  probably  its  outstanding 
characteristic  when  considered  in  relation  to  its  value,  ard 
since  the  harvest  occurs  but  once  each  year  and  the  corkwood 
comes  to  market  soon  after  the  crop  is  taken,  a  large  stock 
must  necessarily  be  kept  on  hand  by  cork  factories.  The  raw 
material  is  frequently  purchased,  or  contracted  for,  a  year  in 
advance  of  its  fabrication.     Thus  great  piles  appear  in  the 


•Gilbert     E.     Steelier,     1914,     "Cork— Its     Origin     and     Industrial     Uses,' 
Nostrand  Co.,  New  York,  N.   Y. 


USES  OF  CORKWOOD  AND  CORK  WASTE  19 

yards  and  sheds  of  cork  plants,  covering  much  area  and  in- 
volving considerable  capital,  for  a  shortage  in  raw  material 
would  not  only  throw  men  out  of  work  and  put  the  plant  into 
disuse  but  would  cause  the  loss  of  much  business  through  in- 
ability to  supply  the  trade  with  first-grade  cork  materials,  the 
other  grades  always  being  compelled  to  await  a  favorable 
market. 

For  whatever  purpose  it  is  to  be  used,  all  corkwood  upon 
reaching  the  factory  is  again  sorted  by  highly  skilled  men ; 
and  the  original  twenty  or  twenty-five  grades  are  re-classed 
into  perhaps  one  hundred  and  twenty-five  or  one  hundred  and 
fifty  grades,  according  to  quality  and  thickness.  Success  in 
the  "cork  business"  hinges  on  the  care  and  skill  displayed  in 
the  various  sorting  operations  that  are  meticulously  followed 
at  every  step  from  the  stripping  of  the  bark  to  the  packing 
of  the  finished  product  for  delivery  to  consumers.  So  slight 
is  the  difference  between  many  of  the  grades  that  the  inexperi- 
enced eye  would  detect  none  whatever,  yet  the  speed  with 
which  this  sorting  work  is  skillfully  done  is  often  astounding. 

The  importance  of  the  initial  sorting  operations  is  increas- 
ing as  the  uses  of  cork  increase;  because  various  grades  can 
now  be  used  for  so  many  different  things,  without  longer  being 
thought  of  as  a  by-product.  In  order  that  the  full  value  be 
obtained  from  all  corkwood,  the  sorter  must  have  a  thorough 
understanding  of  the  uses  to  which  the  many  grades  of  the 
material  may  be  put,  and  for  that  reason  he  is  now  thought 
of  as  an  expert  and  a  valuable  member  of  the  manufacturing 
organization. 

13, — Cork  Stoppers. — No  account  of  the  uses  of  corkwood 
and  the  utilization  of  cork  waste  can  be  given  without  at  least 
a  short  description  of  the  modern  processes  followed  in  manu- 
facturing cork  stoppers,  for  the  waste  from  the  production  of 
these  stoppers  has  long  been  an  appreciable  percentage  of  the 
total  cork  waste  annually  made  available  for  utilization, 
although  this  percentage  is  now  decreasing. 

The  sorted  slabs  of  corkwood  are  first  placed  in  a  steam 
box,  which  process  increases  its  flexibility  greatly,  its  bulk 
slightly,  and  otherwise  prepares  it  for  the  mechanical  opera- 
tions  that   rapidly    follow.      First,    the    steamed   corkwood   is 


20  CORK  INSULATION 

usually  scraped,  often  ])y  hand  and  sometimes  by  knives 
mounted  on  a  \'ertical  shaft  revolving  at  about  1,500  r.p.m.,  to 
remove  the  hard-lDack,  or  "raspa,"  provided  this  operation  was 
not  satisfactorily  performed  at  the  time  of  boiling.  The  cork 
slabs  are  next  cut  into  strips  of  width  equal  to  the  length  of 
the  stopper  to  be  cut,  because  the  cutting  is  done  across  and 
not  with  the  grain  of  the  bark.  A  circular  knife  does  this 
slicing,  following  which  the  strips  go  to  the  "blocking"  ma- 
chine. There  a  tubular  punch,  with  sharpened  edges  and  of 
given  diameter,  is  rotated  at  about  2,000  r.p.m.  to  punch  or 
cut  out  thousands  of  cork  stoppers  per  day,  although  the 
operator  must  use  caution  in  avoiding  defective  spots  and  at 


FIG.     15.— CORK    PUNCHINGS— STOPPERS    REMOVED. 

the  same  time  must  keep  the  punchings  as  close  as  possible  to 
minimize  the  waste.  Next,  smaller  stoppers  are  punched  from 
the  waste  from  the  first  punchings,  if  quality  and  remaining 
area  permit,  for  every  economy  of  raw  stock  must  be  followed. 
These  stoppers  have  straight  sides,  but  if  tapered  corks  are 
desired,  larger  in  diameter  at  the  top  than  at  the  bottom,  the 
cylindrical  pieces  must  be  handled  on  another  machine  where 
a  circular,  razor-edged  knife,  revolving  at  top  speed  and  set 
at  the  proper  taper  angle  to  the  cork  to  be  shaped,  takes  off 
the  necessary  cutting  in  the  form  of  a  very  thin  cork  shaving. 

14. — Cork  Disks. — The  wide  use  of  the  patented  "Crown" 
bottle  cap,  with  which  the  reader  is  undoubtedly  familiar, 
requiring  a  thin  cork  disk,  created  an  outlet  for  very  thin 
bark  for  which  there  was  virtually  no  previous  demand.  A 
revolving  blade  slices  the  cork  bark,  on  a  plane  parallel  to 
its    "back"   and    "belly",    to    the   required    thickness,    ranging 


USES  OF  CORKWOOD  AND  CORK  WASTE  21 

from  one-eighth  to  one-quarter  inch,  and  from  these  sheets 
the  natural  cork  disks  are  punched.  A  great  deal  of  cork 
waste  results  from  this  manufacturing  process,  and  its  utiliza- 
tion is  important  enought  to  form  virtually  a  separate  branch 
of  the  corkwood  industry. 

The  manufactured  stoppers  and  disks  must,  in  their  turn, 
be  sorted  as  to  grade  and  quality.  They  are  then  washed 
and  bleached  by  soaking  in  water  and  a  chemical,  and  are 


-CORK   PU>-CHINGS— DISKS    RExMOVED. 


then  dried  by  spinning  in  a  perforated  centrifugal  cylinder 
mounted  within  a  metal  jacket  connected  to  a  drain.  Some 
stoppers,  usually  "straights",  and  all  disks,  are  given  a  bath 
of  hot  paraffin,  or  glycerine  and  paraffin,  which  improves  their 
resistance  and  retards  discoloration,  the  operation  usually 
being  done  in  a  steam  jacketed  kettle  and  then  "tumbled"  to 
remove  the  excess  water  and  paraffin. 

15. — Artificial  Cork. — The  working  up  of  the  waste  from 
corkwood,  and  virgin  cork,  which  is  classed  as  waste,  into 
many  products  of  utility  and  value  is  probably  the  most  im- 
portant phase  of  the  cork  business  today,  just  as  the  success- 


22  CORK  INSULATION 

ful  utilization  of  by-products  in  any  modern  industry  is  usu- 
ally necessary  for  successful  operation. 

It  was  noted  that  in  the  handling  of  corkwood  the  best 
was  utilized  first;  and  similarly,  in  the  working  up  of  cork 
waste,  the  best  is  granulated  in  an  iron  rotary  cutter  mill,  of 
size  that  will  pass  a  >^-inch  mesh,  screened  and  mixed  with 
an  unusually  tenacious  glue,  dried  by  steam,  hydraulically 
pressed  into  sheets,  dried  again,  and  then  punched  out  into 
"composition"  disks  for  Crown  caps,  gaskets,  insoles  and  a 
variety  of  products,  frequently  termed  "artificial"  cork 
products. 


:ai^r- 


FIG.    17.— CORK  INSOLES   FOR   SHOES. 

Granulated  cork  for  many  purposes  is  made  by  grinding 
the  waste  in  a  metal  roller,  cage  or  bur  mill,  and  screening 
into  various  degrees  of  fineness.  If  cork-flour  is  recjuired,  a 
tube  mill  is  used. 

The  manufacture  of  "Spanish  black"  for  use  as  a  base  for 
oil  paints  of  the  same  color,  is  produced  from  cork  waste  by 
burning  inferior  grades  in  a  retort,  and  grinding  the  carbon- 
ized material  in  a  ball  mill  until  the  required  fineness  is  ob- 
tained. 

16. — Cork  Insulation. — Probably  the  most  important  use 
to  which  cork  waste  is  now  being  put,  and  which  rivals  the 
cork  stopper  industry,  is  in  the  manufacture  of  cork  insulation 
for  the  retarding  of  heat  and  sound. 

Steam  pipes  are  insulated  to  prevent  heat  from  escaping; 
cold  rooms  and  cold  pipes  are  insulated  to  prevent  heat  from 
entering.  Cork  is  employed  as  a  thermal  insulation  to  prevent 
the  entrance  of  heat,  or  to  preserve  cold  temperatures ;  and 
its  success,  either  in  board  or  slab  form  for  application  to 


USES  OF  CORKWOOD  AND  CORK  WASTE 


23 


floors,  walls  and  ceilings  of  cold  rooms,  or  in  special  molded 
forms  for  ready  application  to  cold  pipes  and  fittings,  is  due 


FIC.    18.— PURE    CORKBOARD    INSULATION— 1,    H/o,    2,    3,    AND   4-INCII 
THICKNESSES,    IN    STANDARD    12X36    INCH    SHEETS. 

ii(_»t  alone  to  its  remarkable  heat  retarding  properties  and  its 
ready  adaptability  but  i^iore  particularly  to  its  entire  freedom 


ITG.   19.— CORK  PIPE  COVERING  FOR  REFRIGERATED  LINES  AND  TANKS. 


24 


CORK  INSULATION 


from  capillarity.  This  property,  the  force  that  causes  a  blotter 
to  suck  up  ink,  is  entirely  lacking  in  cork,  as  evidenced  by 
its  long  and  successful  use  as  stoppers  in  vessels  containing 
liquids. 

Machines  are  insulated — perhaps  more  properly  spoken  of 
today  as  isolated— to  permanently  reduce  the  transmission  of 
vibration  and  sound  to  an  irreducable  minimum.     Cork  iso- 


hm 


r^ 
^ 


Za 


-  ".  *-    .  -"- '.  "^  :^  ", 


"-.V  ^':-'-' 
!■■-■.-  r 


FIG.    20.— MACHINE    BASE    COMPLETELY    ISOLATED    WITH    CORKBOARD 
INSULATION    TO    REDUCE    VIBRATION    AND    NOISE. 


lation  is  already  widely  used  in  the  industries;  but,  since  it 
takes  so  little  to  accomplish  so  much,  the  total  quantity  of 
cork  consumed  in  its  manufacture  is  a  small  factor  in  the  cork 
industry, 

Cork  insulation  takes  on  several  forms  of  corkboard,  or 
sheet  cork,  and  molded  cork  pipe  covering;  and  it  is  the 
detailed  treatment  of  the  uses  of  these  remarkable  cork  prod- 
ucts that  shall  comprise  the  greater  part  of  this  text. 


CHAPTER  IV. 

EARLY  FORMS  OF  CORK  INSULATION. 

17. — Natural  Cork  and  Composition  Cork. — The  first  men- 
tion of  the  use  of  cork  as  insulation  appears  to  be  by  the 
elder  Pliny  in  the  first  century  of  the  Christian  era  when  he 
called  attention  to  its  use  by  women  as  winter  foot  gear. 
Undoubtedly  it  was  utilized  as  sandals  because  of  its  insulat- 
ing qualities  and  its  freedom  from  capillarity.  Pliny  spoke 
of  cork  bark  being  used  as  a  covering  for  roofs.  John  Evelyn, 
the  English  writer  and  diarist  (1620-1706),  mentions  that 
cork  was  much  used  by  old  people  for  linings  to  the  soles  of 
their  shoes.  The  poor  of  Spain  laid  planks  of  cork  on  the 
floor  like  tiles,  to  obviate  the  need  for  a  floor  covering  that 
would  be  warm  to  the  touch.  They  also  lined  the  inside  of 
their  stone  houses  with  cork  bark,  to  make  their  homes  easier 
to  heat  and  to  correct  the  precipitation  of  moisture  on  the 
walls.  Ground  cork  and  India  rubber  formed  the  basic  in- 
gredients of  the  quiet,  resilient  floors  of  the  reading  rooms 
of  the  British  Museum.  Bee  hives  have  long  been  construcced 
of  pieces  of  cork  bark,  because  of  its  warmth  to  the  touch. 
Shelves  of  cork  have  been  used  for  centuries  to  preserve  ob- 
jects from  dampness.  The  primitive  races  of  northern  Africa 
used  cork  mixed  with  clay  for  the  walls  of  their  crude  dwell- 
ings, and  cork  slabs  as  roof  tiles.  Cork  was,  and  still  is, 
the  basis  in  Europe  for  certain  cenents  and  plastics  for  pre- 
venting the  escape  of  heat,  which  are  formed  to  steam  pipes, 
and  hot  surfaces  in  general.  Powdered  cork  and  starch  were 
molded  into  cylinders  to  fit  pipes  of  different  sizes,  and  were 
then  split  and  made  ready  for  application  to  pipes  requiring 
insulation,  after  which  the  cork  composition  was  spirally 
wrapped  with  cloth  and  coated  with  tar  or  pitch.  Narrow 
cork  pieces  were  laid  around  steam  pipes,  as  lagging,  wired 

25 


26 


CORK  INSULATION 


in  place  and  spirally  wrapped  and  coated.  Cork  was  early 
used  by  the  medical  profession  because  of  its  sound  isolation 
qualities,  as  lining  for  doors  of  consulting  rooms  and  as  floors 
in  hospitals.  In  tropical  countries,  cork  lined  hats  and  cork 
helmets  have  long  served  to  prevent  sunstroke.  Brick  paste, 
as  it  was  called,  was  made  by  mixing  the  coarsest  cork 
poAvder  with  milk  of  lime,  compressed  into  bricks  and  slabs, 
dried  and  used  for  the   covering  of  damp  walls  and   pitched 


FGI.    21.— CORK    TILE    FLOOR    IN    MODERN    OFFICE. 


roofs.  In  gunpowder  plants  and  powder  storage  magazines, 
such  composition  slabs  prevented  the  caking  of  the  powder 
through  dampness ;  and  used  under  wood  flooring,  they  de- 
stroyed the  sound  vibrations. 

Thus,  it  will  be  noted  that  the  thermal  insulating,  as  well 
as  the  sound  isolating,  qualities  of  cork  bark  were  known 
and  utilized,  although  probably  not  very  clearly  understood, 
as  early  as  the  year  One.  Many  of  these  uses  have  persisted 
through  the  ages* ;  for  cork  insoles  are  today  an  important 


•See  appendi.x  for  "Pulverized  Cork — Subirine"  and  "Cork  as  a  Building  Material." 


EARLY  FORMS  OF  CORK  INSULATION 


27 


item  in  the  construction  of  high  grade  shoes,  cork  tile  floors 
are  essential  to  edifices  and  libraries,  cork  linoleum  is  so 
common  in  public  buildings  and  in  certain  types  of  homes  as 
to  be  classed  as  essential,  and  corkboard  effectively  and  effi- 
ciently prevents  condensation  on  and  the  flow  of  heat  through 
the  walls  and  roofs  of  buildings.  All  that  was  needed  to 
establish  cork  as  the  standard  insulation  of  the  world  was 
the  discovery  of  a  practical   method  of  utilizing  cork  waste 


-CORKBOARD     INSULATION     BEING     APPLIED    TO     SAW-TOOTH 
ROOF    CONSTRUCTION. 


in  the  form  of  molded  slabs  or  boards  of  convenient  size, 
ample  strength  and  high  permanent  insulating  value  under 
actual  service  conditions. 

18. — Impregnated  Corkboard. — About  the  year  1890  the 
German  firm  of  Griinzweig  &  Hartmann  acquired  patents  in 
Germany  and  in  the  United  States  for  a  type  of  insulation 
known  as  "Impregnated  Corkboard",  and  soon  became  the 
leaders  in  their  own  country  in  the  manufacture  of  these 
"impregnated"  cork  slabs  for  insulating  purposes,  particularly 


28  CORK  INSULATION 

for  cold  storage  work.  The  United  States  patent  rights  for 
this  new  type  of  insulation  were  subsequently  acquired  by 
the  Armstrong  Cork  Company  of  Pittsburgh,  about  the  year 
1900,  following  which  a  plant  for  its  manufacture  was  estab- 
lished at  Beaver  Falls,  Pa.,  such  location  being  selected 
principally  because  the  necessary  clay  for  the  preparation  of 
the  foreign  binder  to  stick  the  granules  of  cork  together  was 
available  there  in  generous  quantity  and  at  a  point  not  far 
distant  from  Pittsburgh. 

The  business  grew  rapidly,  especially  among  the  brewers, 
for  the  insulation  of  their  cellars ;  but  it  was  soon  discovered 
that  this  impregnated  corkboard  was  inferior  in  insulating 
quality,  and  in  structural  strength  in  service,  to  a  brand  of 
"pure"  corkboard  being  made  under  the  patents  of  one  John 
T.  Smith,  an  American,  and  subsequently  the  manufacture 
and  use  of  the  impregnated,  or  "composition,"  corkboard  gave 
way  entirely  to  the  pure  corkboard  insulation. 


CHAPTER  V. 

DISCOVERY   OF  SMITH'S  CONSOLIDATED   CORK, 
AND  THE  FIRST  PURE  CORK  INSULATION. 

19. — Smith's  Discovery. — The  manufacture  of  pure  cork 
insulation  was  begun  in  1893,  in  the  United  States,  under  the 
original  John  T.  Smith  patents,  by  Messrs.  Stone  and  Duryee. 
Cork  covering  was  produced  first,  and  then  the  manufacture 
of  pure  corkboard  followed  within  a  very  few  years. 

It  is  interesting  to  know  that  the  discovery  of  the  process 
of  baking  cork  particles  under  pressure  to  bind  them  to- 
gether, which  later  made  pure  cork  insulation  possible,  was 
purely  an  accident ;  and  that  the  process  was  not  thought  of 
in  connection  with  cork  covering  and  corkboard  until  Messrs. 
Stone  and  Duryee  later  applied  it  to  that  purpose. 

In  the  "Boat  Works"  of  John  T.  Smith  on  lower  South 
Street,  on  the  East  River,  in  New  York,  was  a  large  cast-iron 
kettle  with  a  fire  box  under  it,  the  kettle  being  used  to  steam 
oak  framing  for  row  boats  that  Smith  manufactured  there  for 
many  years.  He  also  produced  boat  fenders,  life  preservers 
and  ring  buoys,  in  the  manner  common  in  those  days,  by  pack- 
ing granulated  cork  in  canvas  jackets.  Girls  packed  the  cork 
in  these  jackets,  using  tin  forms  or  cylinders  to  keep  the  can- 
vas distended  until  filled.  One  of  these  cylinders  became 
clogged  in  the  hands  of  one  of  Smith's  employees  and  was 
laid  aside  for  the  moment,  but  it  inadvertently  rolled  into 
the  dying  embers  of  the  fire  box  during  clean-up  late  that 
evening. 

Early  the  next  morning.  Smith,  owner  and  fireman,  cleaned 
out  the  fire  box  and  found  his  misplaced  utensil.  But  the 
hot  ashes  had  not  consumed  the  cork  particles  that  had 
clogged  it.     The  heat  had  been  sufficient  merely  to  bind  the 

29 


30 


CORK  INSULATION 


very  substantial   chocolate- 
brown  cork  cylinder. 

Smith  noted  this  peculiar  fact  with  much  interest,  if  not 
with  actual  astonishment,  and  put  the  tin  form  and  cork 
cylinder  aside  for  future  secret  study  and  investigation.  He 
repeated  the  original  and  wholly  unintentional  experiment 
enough  times  to  satisfy  himself  that  for  some  good  reason  a 
certain  degree  of  heat  applied  for  a  given  time  served  to  glue 
cork    particles    together    without    the    addition    of    a    foreign 


FIG.  23.— ARTIST'S  CONCEPTION  OF  THE  DISCOVERY  OF  PURE   CORK- 
HOARD  INSULATION   BY  JOHN  T.   SMITH. 

substance  or  binder  of  any  kind  or  character,  to  produce  what 
he  later  termed  "Smith's  Consolidated  Cork".  He  thereupon 
applied  for  and  was  granted  basic  patents  in  the  United 
States,  Germany,  France  and  England  covering  the  broad 
principles  involved. 

20. — Cork  Covering  for  Steam  Pipes. — In  1893  Messrs. 
Stone  and  Duryee  purchased  the  Smith  patent  rights  for  the 
United  States,  France  and  England  and  began  the  manufac- 
ture, at  No.  184-6  North  Eighth  street,  Brooklyn,  New  York, 
of  asbestos-lined  cork  covering  for  steam  pipes,  the  sugges- 
tion probably  having  come  to  Junius  H.  Stone,  who  had 
previously  been  engaged  in  the  steam  pipe  covering  business, 
from  the  original  Smith  cork  cylinder,  which,  incidentally, 
Smith  had  failed  to  utilize   to  any  good   purpose   whatever. 


PURE  CORK  ACCIDENTALLY  CONSOLIDATED  31 

But  not  long  thereafter  the  patent  rights  on  "85  per  cent 
Magnesia"  steam  pipe  covering  expired,  and  the  resultant 
competition  so  reduced  prices  as  to  seriously  interfere  with 
the  further  sale  of  the  cork  product. 

21. — Cork  Covering  for  Cold  Pipes. — Then  the  Engineering 
department  of  the  United  States  Navy  became  interested  in 
molded  cork  covering  for  cold  pipes,  to  replace  hair  felt  and 
such  other  fibrous  materials  as  possessed  a  marked  affinity  for 
moisture,  and  it  was  subsequently  tried  out  as  insulation  for 
brine  lines  on  one  of  the  large  battleships  then  building. 

The  adaptability  and  suitability  of  this  very  early  form 
of  pure  cork  covering  for  cold  lines  was  quickly  apparent 
to  the  Navy's  engineers,  and  the  material  rapidly  found  favor 
in  other  Governmental  departments.  Thus  the  real  field  of 
usefulness  for  Smith's  Consolidated  Cork — as  an  insulating 
material  for  cold  surfaces — was  discovered ;  and  soon  there- 
after, with  the  encouragement  of  the  Navy  department  again, 
the  firm  of  Stone  &  Duryee  began  the  manufacture  of  the 
very  first  pure  corkboard  that  was  ever  produced,  sold  or 
used. 

It  cannot  be  out  of  place  to  remark  here  that  the  various 
U.  S.  Governmental  departments  are  constantly  on  the  look- 
out for  new  and  better  materials  for  use  in  the  construction 
of  governmental  equipment  of  every  conceivable  sort.  To  our 
Government's  engineers  may  be  credited  the  discovery,  early 
development  or  initial  successful  use  of  many  materials  and 
products  that  have  influenced  the  course  of  human  progress. 
Merely  as  an  instance,  this  is  taken  from  the  August  23d, 
1926,  issue  of  the  Chicago  Daily  Tribune,  under  the  caption  of 
"Science  Marches  On" : 

Army  experts  in  aerial  photography,  improving  a 
process  invented  by  the  Eastman  Kodak  Company, 
are  able  to  take  photographs  not  only  at  great  dis- 
tances but  through   mist  and   smoke  screens. 

22, — Pure  Corkboard. — Mr.  Harvey  H.  Duryee,  of  the  firm 
of  Stone  &  Duryee,  was  of  French  Hugenot  descent,  and  it 
pleased  him  to  designate  the  products  of  his  firm  "Nonpareil", 
from  the  French  words  "non  pared",  meaning  no  parallel, 
or  no  equal.     The  firm  of  Stone  &  Duryee  subsequently  be- 


Z2 


CORK  INSULATION 


came  The  Nonpareil  Cork  Works,  and  with  the  construction 
of  a  factory  at  Camden,  N,  J.,  it  became  the  Nonpareil  Cork 
Manufacturing  Company. 

In  June,  1904,  the  Armstrong  Cork  Company  purchased 
the  patents,  plant  and  business  of  the  Nonpareil  Cork  Manu- 
facturing  Company;  and,  by  the   time   the   patents   expired. 


FIG.    24.— AN   EXAMPLE   OF  THE   VERSATILITY   OF   MODERN    CORK   PIPE 

COVERING,    LAGS    AND    DISKS,    ON    TANK    HEADER,    RECEIVER, 

PIPING  AND  FITTINGS. 


both  pure  corkboard  insulation*  and  cork  pipe  covering^  were 
the  standard  of  the  world  wherever  the  use  of  refrigeration 
had  been  scientifically  introduced. 


*See  Appendix  for  "Some  Uses  of  Corkboard  Insulation". 
tSee   Appendix    for   "Cork    Pipe    Covering   Specifications"   and 
Proper   Application   of   Cork    Pipe   Covering." 


'Instructions   for   the 


CHAPTER  VI. 
EXTENT  OF  THE  CORK  INDUSTRY. 

23. — Is  Source  of  Supply  Adequate? — The  question  that  is 
most  frequently  asked  today  is  this:  "Can  the  production  of 
corkwood  be  increased  sufficiently  by  the  cork  producing 
countries  to  keep  pace  with  the  world's  constantly  increasing 
demand  for  cork  products  of  every  kind?" 

In  attempting  an  answer  to  such  a  question,  if  indeed  an 
answer  should  be  attempted,  it  must  be  remembered  that 
corkwood  is  an  agricultural  product,  and  that  in  agriculture 
price  controls  production,  with  certain  important  limitations, 
rather  than  production  establishing  price  as  it  does  in  many 
of  the  industries  not  associated  with  agriculture.  In  other 
words,  if  an  agricultural  product  grown  in  volume  will  bring 
a  price  that  will  make  such  growing  of  the  product  profitable, 
it  will  continue  to  be  produced  in  volume ;  otherwise,  not.  If 
that  volume  demand  should  grow  beyond  the  ultimate  capac- 
ity of  the  producing  soil  and  climate,  then  other  soil  will  be 
prepared  and  utilized  in  a  suitable  climate,  if  that  is  possible 
and  not  too  costly.  Now  a  look  back  into  the  history  of  the 
cork  industry  should  furnish  much  information  and  possibly 
serve  as  a  guide  in  reaching  conclusions  about  the  ultimate 
extent  of  the  cork  industry,  with  particular  emphasis  upon 
cork  insulation. 

24. — Cork  Stopper  Industry. — The  cork  stopper  industry, 
which  was  for  many  years  the  most  important  branch  of  the 
cork  industry,  had  its  permanent  origin  in  the  town  of 
Llacostera,  Province  of  Gerona,  Spain,  late  in  the  year  1750,* 
and   was   incident   to   the  real   beginnings   of  the   use  of  the 


•Gilbert    E.    Stecher,    1914,    "Cork— Its    Origin   and    Industrial   Uses,"    D. 
trand   Co.,  New    York,   N.   Y. 

33 


34 


CORK  INSULATION 


glass  bottle,  although  corkwood  was  used  centuries  before 
as  stoppers  for  casks  and  other  kinds  of  liquid-containing 
vessels.  The  cork  trade  was  later  disrupted  by  the  many 
wars  that  followed  one  another  in  rapid  succession,  which 
drove  the  industry  to  the  mountains  to  struggle  for  years  until 
some  semblance  of  peace  was  restored.  The  principal  dan- 
gers having  passed,  the  cork  stopper  industry  slowly  but 
surely  grew  until  it  virtually  became  a  necessity  in  the  life 
of  Spain. 


FIG.  25.— LOADING  CKATEU  COKKBOAKD  AT  PALAMOS,  Sl'AlX. 


It  was  customar}-  in  those  days  to  hold  all  manufacturing 
processes  as  valuable  secrets,  but  the  cork  stopper  industry 
of  Spain  soon  attracted  so  much  attention  that  other  and 
neighboring  countries  sought  to  learn  the  secrets  of  its  pro- 
cesses. French  agents  in  the  Province  of  Catalonia  obtained 
sufficient  information,  it  is  said,  to  return  to  France  and 
establish  their  own  plants,  which  greatly  disturbed  the  Span- 
ish manufacturers  because  they  had  never  had  any  competi- 
tion up  to  that  time.  But  by  about  1850  the  trade  in  cork 
and   cork   products  had  grown   so  that  there   was   plenty  of 


EXTENT  OF  CORK  INDUSTRY 


35 


business  for  all.  and  the  industry  expanded  until  it  surpassed 
the  expectations  of  the  most  optimistic.  In  fact,  a  shortage 
of  corkwood  came  about  in  Spain ;  and.  in  an  effort  to  fill 
the  demands,  the  cork  bark  was  stripped  from  the  trees  more 
frequently  than  was  usual  or  desirable,  and  as  a  consequence 
the  grade  deteriorated  until  the  situation  became  alarming. 

25. — Cork  a  National  Necessity. — The  Spanish  Government 
then  passed  the  necessary  laws  to  ])rotect  its  cork  forests  as 


FIG.    26.— CORK    REFUSE— USED    IN    THE    MANUFACTURE    OF    MANY 
"ARTIFICIAL"    CORK    PRODUCTS. 

a  national  necessity,  these  laws  governing  the  stripping  of 
the  corkwood  from  the  trees.  But  the  demand  for  corkwood 
kept  right  on  growing  in  other  countries,  and  the  raw  stock 
came  to  be  so  heavily  exported  from  Spain  and  Portugal  that 
it  finally  interfered  so  seriously  with  the  local  production  of 
finished  cork  products  as  to  bring  about  a  convention  of  the 
principal  representatives  of  the  cork  industry  in  Madrid,  in 
December,  1911.  Resolutions  were  passed  calling  upon  the 
Spanish  Government  to  impose  an  export  duty  on  corkwood, 
ranging  from  about  90  cents  to  $90.00  per  ton. 

New  export  duties  were  then  decided  upon  by  the  Govern- 


36  CORK  INSULATION 

merit  and  an  effort  was  made  to  put  the  new  laws  in  force 
in  1912,  but  all  these  efforts  were  without  much  success.  In 
Portugal,  one  of  the  restrictive  laws  that  were  passed  made 
it  impossible  to  export  from  the  country  pieces  of  corkwood 
larger  than  about  4x8  inches.  That  law,  while  almost  never 
enforced,  still  remains  to  harry  the  inexperienced  buyer  who 
has  failed  to  provide  in  advance  for  its  temporary  nonexist- 
ence, so  to  speak. 

26.— Effect  of  U.  S.  Tariff  A.ct  of  1913.— For  one  reason  or 
another,  the  governments  of  Portugal  and  Spain  both  failed 
in  their  efforts  to  restrict  the  exportations  of  raw  cork,  al- 
though the  cork  manufacturing  industry  remains  very  strong 
in  both  of  these  countries,  particularly  in  Spain.  Consider- 
able impetus  was  given  the  manufacture  of  cork  insulation 
in  Spain  when  the  United  States  Tariff  Act  of  1913,  which 
reduced  the  United  States  import  on  finished  cork  insulation 
to  a  specific  duty  of  Y^c  per  pound,  became  effective.  The  Act 
of  1922  restored  the  former  rate  of  duty  of  the  Act  of  1909, 
or  30  per  centum  ad  valorem*,  but  meanwhile  several  large 
insulation  factories  were  constructed  in  Spain  and  one  in 
Portugal  and  the  size  of  these  investments  coupled  with  the 
constantly  mounting  labor  rate  in  the  United  States  keeps 
these  foreign  plants  of  domestic  concerns  operating  at 
capacity. 

The  United  States  Tariff  Commission's  Comparison  of 
Tariff  Acts— 1922,  1913  and  1909— subdivides  "Cork"  into 
eighteen  groups,  as  follows : 

TARIFF    SUBDIVISIONS    OF    CORK   INTO    GROUPS. 

Paragraph  under  act  of 

Description  1922        1913        1909 

Cork:  No.         No.         No. 

Artificial    and    manufactures    of 1412  340  429 

Bark,  squares,   etc 1412  340  429 

Bark,    unmanufactured    1559  464  547 

Carpet     1020  276  347 

Composition    or    compressed    1412  340  429 

Disks     1412  340  429 

Granulated   or    ground 1412  340  429 

Insulation    1412  340  429 

Manufacturers    of.    n.    s.    p.    f 1412  340  429 

Paper    1412  340  429 

*Duties  imposed  by  a  government  on  commodities  imported  into  its  territory  from 
foreign  countries  are  designated  as  specific  and  ad  valorem — the  former  when  fixed 
at  a  specified  amount,  the  latter  when  requiring  payment  of  a  sum  to  be  ascertained 
by  a  determined   percentage  on   the  value  of   the  goods   imported. 


EXTENT  OF  CORK  INDUSTRY  37 

TARIFF  SUBDIVISIONS   OF   CORK  INTO   GROUPS.— Confinued 

Paragraph  under  act  of 

Description  1922        1913        1909 

Cork:  No.         No.         No. 

Refuse   and    shavings 15S9  464  547 

Stoppers     1412  340  429 

Substitutes    1412  340  429 

Tile    1412  340  429 

Wafers     1412  340  429 

Washers     1412  340  429 

Waste    1559  464  547 

Wood   or   cork   bark,   unmanufactured 1559  464  547 

Act  of  1922 
Paragraph   1020. — Linoleum,   including   corticine   and   cork   carpet, 
35  per  centum  ad  valorem;  floor  oilcloth,  20  per  centum  ad  valorem; 
mats  or  rugs  made  of  linoleum  or  floor  oilcloth  shall  be  subject  to  the 
same  rates  of  duty  as  herein  provided  for  linoleum  or  floor  oilcloth. 

Paragraph  1412. — Cork  bark,  cut  into  squares,  cubes,  or  quarters, 
8  cents  per  pound;  stoppers  over  three-fourths  of  an  inch  in  diameter, 
measured  at  the  larger  end,  and  discs,  wafers,  and  washers  over 
three-sixteenths  of  one  inch  in  thickness,  made  from  natural  cork 
bark,  20  cents  per  pound;  made  from  artificial  or  composition  cork, 
10  cents  per  pound;  stoppers,  three-fourths  of  one  inch  or  less  in 
diaineter,  measured  at  the  larger  end,  and  discs,  wafers,  and  washers, 
three-sixteenths  of  one  inch  or  less  in  thickness,  made  from  natural 
cork  bark,  25  cents  per  pound;  made  from  artificial  or  composition 
cork,  121/2  cents  per  pound;  cork,  artificial,  commonly  known  as  com- 
position or  compressed  cork,  manufactured  from  cork  waste  or  gran- 
ulated cork,  in  the  rough  and  not  further  advanced  than  in  the  form 
of  slabs,  blocks,  or  planks,  suitable  for  cutting  into  stoppers,  discs, 
liners,  floats,  or  similar  articles,  6  cents  per  pound;  in  "rods  or  sticks 
suitable  for  the  manufacture  of  discs,  wafers,  or  washers,  10  cents 
per  pound;  granulated  or  ground  cork,  25  per  centum  ad  valorem; 
cork  insulation,  wholly  or  in  chief  value  of  cork  waste,  granulated  or 
ground  cork,  in  slabs,  boards,  planks,  or  molded  forms;  cork  tile; 
cork  paper,  and  manufactures,  wholly  or  in  chief  value  of  cork  bark 
or  artificial  cork  and  not  specially  provided  for,  30  per  centum  ad 
valorem. 

Paragraph  1559. — Cork  wood,  or  cork  bark,  unmanufactured,  and 
cork  waste,  shavings,  and  cork  refuse  of  all  kinds  (Free). 

Act  of  1913 
Paragraph  276. — Linoleum,  plain,  stamped,  painted,  or  printed,  in- 
cluding corticine  and  cork  carpet,  figured  or  plain,  also  linoleum 
known  as  granite  and  oak  plank,  30  per  centum  ad  valorem;  inlaid 
linoleum,  35  per  centum  ad  valorem;  oilcloth  for  floors,  plain,  stamped, 
painted,  or  printed,  20  per  centum  ad  valorem;  mats  or  rugs  made 
of  oilcloth,  linoleum,  corticine,  or  cork  carpet  shall  be  subject  to  the 
same  rate  of  duty  as  herein  provided  for  oilcloth,  linoleum,  corticine, 
or  cork  carpet. 


38  CORK  INSULATION 

Paragraph  340. — Cork  bark,  cut  into  squares,  cubes,  or  quarters, 
4  cents  per  pound;  manufactured  cork  stoppers,  over  three-fourths 
of  an  inch  in  diameter,  measured  at  the  larger  end,  and  manufactured 
cork  discs,  wafers,  or  washers,  over  three-sixteenths  of  an  inch  in 
thickness,  12  cents  per  pound;  manufactured  cork  stoppers,  three- 
fourths  of  an  inch  or  less  in  diameter,  measured  at  the  larger  end, 
and  manufactured  cork  discs,  wafers,  or  washers,  three-sixteenths  of 
an  inch  or  less  in  thickness,  15  cents  per  pound;  cork,  artificial,  or 
cork  substitutes  manufactured  form  cork  waste,  or  granulated  cork, 
and  not  otherwise  provided  for  in  this  section,  3  cents  per  pound; 
cork  insulation,  wholly  or  in  chief  value  of  granulated  cork,  in  slabs, 
boards,  planks,  or  molded  forms,  ^  cent  per  pound;  cork  paper,  35 
per  centum  ad  valorem;  manufactures  wholly  or  in  chief  value  of 
cork  or  of  cork  bark,  or  of  artificial  cork  or  cork  substitutes,  granu- 
lated or  ground  cork,  not  specially  provided  for  in  this  section,  30 
per   centum  ad  valorem. 

Paragraph  464. — Cork  wood,  or  cork  bark,  unmanufactured,  and 
cork  waste,  shavings,  and  cork  refuse  of  all  kinds    (Free). 

Act  of  1909 

Paragraph  347. — Linoleum,  corticene,  and  all  other  fabrics  or  cov- 
erings for  floors,  made  in  part  of  oil  or  similar  product,  plain,  stamped, 
painted  or  printed  only,  not  specially  provided  for  herein,  if  nine 
feet  or  under  in  width,  8  cents  per  square  yard  and  15  per  centum 
ad  valorem;  over  nine  feet  in  width,  12  cents  per  square  yard  and 
IS  per  centum  ad  valorem;  and  any  of  the  foregoing  of  whatever 
width,  the  composition  of  which  forms  designs  or  patterns,  whether 
inlaid  or  otherwise,  by  whatever  name  known,  and  cork  carpets,  20 
cents  per  square  yard  and  20  per  centum  ad  valorem;  mats  for  floors 
made  of  oilcloth,  linoleum,  or  corticene,  shall  be  subject  to  the  same 
rate  of  duty  herein  provided  for  oilcloth,  linoleum,  or  corticene; 
oilcloth  for  floors,  if  nine  feet  or  less  in  width,  6  cents  per  square 
yard  and  15  per  centum  ad  valorem;  over  nine  feet  in  width,  10  cents 
per  square  yard  and  15  per  centum  ad  valorem;  .... 

Paragraph  429. — Cork  bark  cut  into  squares,  cubes,  or  quarters,  8 
cents  per  pound;  manufactured  corks  over  three-fourths  of  an  inch 
in  diameter,  measured  at  larger  end,  15  cents  per  pound;  three-fourths 
of  an  inch  and  less  in  diameter,  measured  at  larger  end,  25  cents  per 
pound;  cork,  artificial,  or  cork  substitutes,  manufactured  from  cork 
waste  or  granulated  cork,  and  not  otherwise  provided  for  in  this 
section,  6  cents  per  pound;  manufactures,  wholly  or  in  chief  value 
of  cork,  or  of  cork  bark,  or  of  artificial  cork  or  cork  substitutes,  gran- 
ulated or  ground  cork,  not  specially  provided  for  in  this  section,  30 
per  centum  ad  valorem. 

Paragraph  547. — Cork  wood,  or  cork  bark,  unmanufactured.  (Free). 


EXTENT  OF  CORK  INDUSTRY 


39 


27. — Effect  of  the  World  War. — While  there  was  an  ap- 
parent shortage  of  corkwood  for  a  brief  time  just  prior  to  the 
beginning  of  the  World  War,  yet  the  demand  for  corkwood 
by  France,  Germany.  Austria  and  other  belligerent  countries 
quickly  dropped  off  to  almost  nothing,  which  left  the  United 
States  as  virtually  the  only  country  requiring  any  appreciable 
exports  of  corkwood  or  cork  waste.  The  situation  in  the  cork 
producing  countries  became  rapidly  worse  as  the  war  con- 
tinued until  the  time  soon  came  when  it  did  not  pay,  in  many 
cases,  to  bring  in  the  cork  harvest. 


FIG.    27.— CORKWOOD    STOCKS    ON    HAND   IN    STORAGE    YARD   IN    SPAIN. 

.  In  Catalonia,  for  example,  the  situation  become  so  acute 
at  one  time  that  valuable  cork  oak  trees  were  cut  down  and 
burned  as  fuel  and  the  cork  workers  threatened  to  burn  all 
cork  manufacturing  plants  if  enough  employment  was  not 
*given  them  to  keep  body  and  soul  together.  The  situation 
was  quickly  recognized  as  acute,  and  large  owners  moved 
rapidly  to  provide  enough  relief  to  tide  over  the  difficulties 
occasioned  by  the  World  War.  Sufficient  capital  was  "in- 
vested in  stocks  to  provide  the  cork  workers  with  just  enough 
wages  to  buy  necessary  food  and  drink,  although  it  was  not 
known  then  by  those  owners  and  operators  how  long  they 
would  have  to  continue  the  very  unusual  procedure  before 
the   war  would   end   and   thus   give   them   an   opportunity   of 


40  CORK  INSULATION 

turning  those  stocks  back  into  capital,  regardless  of  whether 
a  profit  could  be  realized  or  a  heavy  loss  would  be  suffered. 

Conservation  of  valuable  cork  forests  and  cork  manufac- 
tories and  the  prevention  of  civil  war  and  incident  loss  of 
life  was  the  first  and  only  consideration  of  those  large  opera- 
tors; but  they  met  the  situation  with  such  remarkable  fore- 
sight attended  by  such  complete  success  that  the  King  of 
Spain  is  said  to  have  personally  thanked  the  men  who  so  ably 
and  generously  gave  of  their  time  and  money. 

28. — Recovery  of  the  Industry. — If  a  crop  of  wheat  is 
wanted  next  year,  the  planting  usually  is  done  in  the  fall  of 
this  year.  With  cork,  however,  it  is  from  eight  to  nine  years 
after  the  stripping  of  the  virgin  bark  before  the  secondary 
bark  can  be  stripped  and  another  equal  period  before  the  first 
real  crop  of  corkwood  is  available.  When  there  is  not  a 
favorable  price  offered  for  corkwood,  the  trees  are  not  stripped, 
that  is,  the  older  ones  that  have  previously  been  brought 
into  bearing  and  are  ready  for  stripping  are  allowed  to  go 
over  another  year,  or  two,  or  three,  as  desired  and  those 
ready  for  their  initial  stripping,  of  the  virgin  bark,  are  not 
touched.  Thus  it  can  be  seen  what  happened  to  much  of  the 
cork  forests  during  the  World  War ;  and  when  the  demand  for 
corkwood  suddenly  returned  to  normal  again,  with  the  re- 
covery of  Europe,  and  with  an  unusually  brisk  demand  in 
the  United  States  due  to  an  active  cold  storage  building 
program,  to  the  adoption  of  corkboard  as  standard  for  house- 
hold refrigerators,  and  to  the  demand  for  corkboard  as  insula- 
tion for  roofs  and  residences,  a  temporary  shortage  of  raw 
cork  waste  was  felt  early  in  1926,  its  price  trebled,  and  the 
price  of  many  finished  cork  products  rose  by  July  first  to 
double  what  they  were  early  in  1925,  all  because  the  raw 
product  supply  could  not,  by  the  nature  of  the  industry,  ex- 
pand suddenly  to  take  care  of  wide  and  sudden  fluctuations  in 
demand. 

The  resultant  (August,  1926)  price  of  cork  waste  aided 
in  bringing  in  a  full  harvest  in  the  cork  producing  countries 
for  the  first  time  since  1914,  many  young  trees  were  put  in 
line  for  productivity  by  receiving  their  initial  stripping,  and 
with  the  complete  cessation  of  the  Riffian  wars  in  Northern 


EXTENT  OF  CORK  INDUSTRY  41 

Africa  much  is  being  done  by  France  and  Spain  to  open  up 
that  enormous  area  of  virgin  cork  forests  as  a  very  appreciable 
future  source  of  supply, 

29. — Changing  Demands, — The  growth  of  "prohibition" 
throughout  the  world  and  the  increasing  substitution  of 
"Crown"  caps  and  screw  closures  for  cork  stoppers  has  ef- 
fected a  material  decrease  in  the  total  quantity  of  corkwood 
required  for  use  in  connection  with  bottles  containing  liquids. 
The  use  of  granulated  cork  for  the  packing  of  glass  and 
fruit  is  decreasing  in  favor  of  certain  very  soft  woods.  The 
world's  demand  for  corkwood  for  miscellaneous  purposes, 
such  as  life  preservers,  floats,  buoys,  etc.,  probably  has  not 
changed  a  great  deal  in  many  years  and  probably  will  not 
change  much  in  the  years  to  come.  The  demand  for  cork 
waste,  however,  for  cork  insulation  has  increased  irregularly 
but  slowly  and  certainl}^  ever  since  pure  corkboard  insulation 
was  first  made  some  thirty-four  years  ago,  the  industry  get- 
ting its  first  important  impetus  when  the  basic  pure  cork 
insulation  patents  expired,  and  its  second  important  impetus 
in  1925  when  corkboard  began  to  be  used  in  large  quantities 
as  a  recognized  essential  insulation  for  electric  household 
refrigerators  and  standard  insulation  for  industrial  roof  slabs. 

At  one  time  the  breweries  utilized  about  two-thirds  of  all 
cork  insulation  that  was  produced.  Then  ice,  ice  cream  and 
cold  storage  plants  replaced  the  breweries  as  the  large  con- 
sumers of  cork  insulation.  The  mechanically-cooled  cork- 
insulated  ice  cream  cabinet  is  replacing  the  ice  plant  as  an 
adjunct  to  the  ice  cream  factory,  the  cork-insulated  mechan- 
ically-cooled commercial  and  household  refrigerators  are  mak- 
ing inroads  on  the  use  of  ice,  and  thus  it  will  be  observed 
that  as  new  applications  are  made  others  are  slightly  reduced, 
so  that  the  world's  urgent  need  for  cork  insulation,  that  is, 
for  use  with  cold  storage  temperatures  where  cork  insulation 
is  now  essential,  has  a  habit  of  slowly  increasing  with  the 
growth  of  population  and  with  the  increasing  per  capita  use 
of  refrigeration  in  the  preservation  of  food.  A  great  propor- 
tion of  all  foodstuffs  is  today  preserved  by  cooling,  one  place 
or  another,  by  ice  or  mechanical  refrigeration,  and  cork  in- 
sulation is  an  essential  item  of  all  cold  storage  equipment. 


42 


CORK  INSULATION 


tip 


EXTENT  OF  CORK  INDUSTRY 


43 


Thus  the  basic  essential  requirements  for  cork  insulation  by 
the  industries  of  the  world  must  be  somewhat  comparable  to 
shfting  sands — constantly  moving  about  but  added  to  but 
slowly.  On  the  other  hand,  there  is  a  growing  demand  for 
cork  insulation  for  use  wherever  moisture  is  encountered,  such 
as  for  the  insulation  of  industrial  roofs,  which  field  is  enorm- 
ous in  scope,  and  if  the  demand  for  corkboard  for  roofs  con- 
tinues at  the  pace  it  has  already  set  for  itself,  then  no  one 
dare  predict  the  ultimate  requirements  for  cork  insulation, 
andvin  turn,  for  cork  waste  and  corkwood. 

Of  course,  if  the  ultimate  cost  were  low  enough,  cork, 
because  it  combines  within  itself  so  many  unusual  and  useful 
qualities,  would  be  utilized  in  many  more  ways  and  to  a  much 
greater  extent  than  it  is  at  present  employed.  Cost,  how- 
ever, is  usually  the  final  determining  factor  in  the  industries 
of  the  world ;  and,  should  the  demand  exceed  the  supply, 
additional  cork  will  be  made  available  or  the  price  of  cork  will 
advance  to  a  point  sufficient  to  discourage  further  increase  in 
its  use  and  consumption.  In  such  event,  possibly  substitutes 
will  be  found  for  enough  of  the  miscellaneous  uses  to  which 
cork  is  put  to  release  sufficient  material  for  all  the  essential 
cork  products,  such  as  cork  insulation,  that  wr)uld  be  required. 

30.— Tables  of  U.  S.  Imports  (1892-1924).— In  order  that 
the  reader  may  form  a  comprehensive  idea  of  the  cork  indus- 
try, past  and  present,  a  number  of  tables  of  cork  imports  into 
the  United  States  from  various  countries  are  given  here. 


IMPORTS  OF  MERCHANDISE 


Fiscal  Year 

Corkwood  or  Cork  Bark 

Unmanufactured 

(Free) 

Cork,  Manufactures  of 
(Dutiable) 

Total  Value  of  Imports 

1892 

1893 

1894 

189.5 

1896 

$1,368,244.00 
1,641,294.00 
985,913.00 
1,049,073.00 
1,209,450.00 
1,-323,409.00 
1,1.52,325.00 
1,147,802.00 
1,444,825.00 
1,729,912.00 
1,816,107.00 
1,737,366.00 
1.484,405.00 
1,729,113.00 

$  321,480.00 
351,731.40 
295,069.00 
351,757.00 
409,887.00 
428,243.00 
294,863.00 
394,.565.00 
464,658.00 
541,083.00 
648,827.00 
8.30,214.00 
810,738.00 

1,009.176.00 

$1,689,724.00 
1,993,025.40 
1.280,982.00 
1,400,830.00 
1,619,.337.00 

1897 

1808 

1,751,6.52.00 
1,447,188.00 

1899 

1,542,367.00 

1900 

1901 

1902 

1903 

1904 

1,909,483.00 
2,270,995.00 
2,464,934.00 
2,567,580.00 
2,295,138.00 

1905 

2,738.319.00 

44 


CORK  INSULATION 


IMPORTS  OF  MERCHANDISE— Con<t«Mcd 
FISCAL  YEAR  OF  1906— JUNE  30,  1905,  TO  JUNE  30.  1906 


IMPORTS  INTO 

UNITED  STATES 

FROM 

Cork  Bark, 
or  Wood 
Unmanu- 
factured' 

Cork  Waste. 
Shavings,  etc. 

Cork  Discs. 

Wafers  and 

Washers 

All  Other 
Manufac- 
tures 

Dollars 

Pounds 

Dollars 

Pounds 

Dollars 

Dollars 

EUROPE: 
Austria  and  Hungary 

7.194 
224 

5 

18 

Bulgaria 

67 

Finland    

Francp  

120.953 
25,147 
50.842 

11.405 

Cprmanv 

139082 

30 

Netberlands 

1 

Norway 

1.774 

988,757 

8,441 

R?miafi^a 



91 

Spain 

481.675 

.1,300.747 

Sweden 

XlSe^'"^'''™ 

6,553 

15,093 

AMERICA: 

1.248 

62 

10 

South  American  Continent 

ASIA: 

r<hlna 

ilf  othere 

2.734 
151,220 

""^M^S^.- 

932 

1,837.134 

1.476.172 

FISCAL   YEAR   OF  1907-JUNE 

30,  1906.  TO  JUNE  30,  1907 

EUROPE: 

Belgium 

22.116 

561 

23 

France 

82.802 
49.261 
92,758 

6.0!; 

Pprmanv 

171,85; 

150 

Norway ...  •  •  •  •      • 

2  5 

1.333,815 

57,608 

Russia  In  Europe 

Spain 

s^m 

1.452,010 

United  Kingdom 

16,206 

19,223 

^^l?ad^^  = 

482 

313 

2 

341 

4 

South  American  Continent 

ASIA: 

y  "'"* 

ilFothCTS 

1 

AFRICA: 

146.708 

AH  others 

3,067 

Totals 

2,356.052 

1,707,930 

■Includes  cork  waste,  shavings,  etc.,  prior  to  July  I,  1918. 


EXTENT  OF  CORK  INDUSTRY 


45 


IMPORTS    OF    MERCHANDISE Continued 

FISCAL  YEAR  OF  1908— JUNE  30.  1907,   TO  JUNE  30.  1908 


IMPORTS  INTO 

UNITED  STATES 

FROM 

Cork  Bark, 
or  Wood 
Unmanu- 
factured' 

Cork  Waste, 
Shavings,  etc. 

Cork  Discs, 

Wafers  and 

Washers 

All  Other 
Manufac- 
tures 

Dollars 

Pounds 

Dollars 

Pounds 

Dollars 

Dollars 

EUROPE: 

116 

Belgium 

Bulgaria 

Finland 

*li 

5  735 

oermany 

322:675 
45 

1,268.611 

76,940 

Russia  in  Europe 

7,164 
467,046 

532 

United  Kingdom 

12.694 

22.125 

AMERICA: 

93 

831 

Central  American  States 

Cuba 

310 

Mexico 

362 

ASIA: 
Cliina 

All  others 

AFRICA: 

Algeria 

132,060 

19 

Totals 

2,092,732 

2,156,274 

1 

FISCAL   YEAR  OF  1909— JUNE 

30,   1908,   TO   JUNE   30,   1909 

EUROPE: 

40 

Finland 

109,263 
53,097 
66,2.58 

2,253 

115,470 

48 

203 

1,197,430 

42,907 

Ruma^a 

Russia  in  Europe 

Spain 

73fi 
453,084 

849,788 

United  Kingdom 

All  others 

3,347 

14.298 

AMERICA: 

235 

Central  American  States. . 

88 

434 

Mexico 

South  American  Continent 

219 

ASIA: 

Japan 

3 

All  others 

AFRICA: 
Algeria 

132,972 

An  fithpri 

2,016,551 

1,025.639 

'Includes  cork  waste,  shavings,  etc.,  prior  to  July  1, 


46 


CORK  INSULATION 


IMPORTS    OF    MERCHANDISE — Continued 
FISCAL  YEAR  OF  1910— JUNE  30,  1909,   TO  JUNE  30.  1910 


IMPORTS   INTO 

UNITED  STATES 

FROM 

Cork  Barli, 
or  Wood 
Unmanu- 
factured' 

Cork  Waste. 
Shavings,  etc. 

Cork  Discs. 

Wafers  and 

Washers 

All  Other 
Manufac- 
tures 

Dollars 

Pounds 

Dollars 

Pounds 

Dollars 

Dollars 

EUROPE: 

9 

Belgium 

58 

4  173 

22 

n 

10S.S60 
20,091 
36,801 

8  098 

r-prnvfriv 

200'256 

Italy 

453 

1,888,738 

51.854 

Russia  in  Europe 

4,200 
913.528 

United  Kingdom 

17.133 

16  539 

AMERICA: 

1.002 

184 

232 

Soutli  American  Continent 

10 

ASIA: 

12 

AFRICA: 

162,655 

Totals 

3.152,280 

1  619  111 

FISCAL  YEAR  OF  1911— JUNE 

33,   1910,   TO  JUNE  33,  1911 

EUROPE: 

Belgium 

Bulgaria 

24 

3 

Finland 

145,323 
85.941 
56.757 
4.384 

Cermaiiv 

1.785,848 

Russia  In  Europe 

4,094 
2.010,216 

Swm?pn 

United  Kingdom 

All  others 

4,151 

AMERICA: 

1,046 

West  IndiM 

ASIA: 

China 

1 

All  others 

AFRICA: 

176,976 

«- 

All  others 

50 

582" 

4.274,810 

■Includes  cork  waste,  shavings,  etc.,  prior  to  July  1,  1918.     sAuatralia. 


EXTENT  OF  CORK  INDUSTRY 


47 


IMPORTS    OF    MERCHANDISE Continued 

FISCAL   YEAR  OF  1912— JUNE  30,  1911,   TO  JUNE  30,  1912 


IMPORTS  INTO 

UNITED  STATES 

FROM 

Cork  Bark, 
or  Wood 
Unmanu- 
factured' 

Cork  Waste. 
Shavings,  etc. 

Cork  Discs. 

Wafers  and 

Washers 

All  Other 
Manufac- 
tures 

Dollars 

Pounds 

Dollars 

Pounds 

Dollars 

Dollars 

EUROPE: 

Austria  and  Hungary 

Belgium 

Bulgaria 

Czechoslovaltia 

4,345 

Finland 

122,414 
72,240 

26.758 

283.325 

358 

2.509 

Netherlands 

Norway 

Poland  and  Danzig 

1.440.491 

52.534 

Rumania 

Russia  in  Europe 

4.525 
1,282.871 

1.972.758 

Sweden .  . 

United  Kingdom 

2.108 

8.137 

All  others 

AMERICA: 

2 

Central  American  States 

Cuba 

Mexico  . 

2 

South  American  Continent 

West  Indies 

ASIA: 

China 

Japan 

23 

All  others 

AFRICA: 

Algeria 

256.385 

Morocco 

All  others 

3,242.319 

2.346.415 

FISCAL  YEAR  OF  1913— JUNE 

30,  1912,   TO  JUNE  30,  1913 

EUROPE: 

Belgium 

230 

5.737 

106.077 
10.661 
115.330 

-i 

Netherlands 

Norway 

Poland  and  Danzig   . 

1.480.329 

47.483 

Rumania 

Russia  in  Europe 

938 
1.250.722 

2.229.266 

Sweden 

United  Kingdom 

All  others 

1.474 

6.097 

AMERICA: 

Central  American  States 

Mexico 

721 

3 

ASIA: 

2 

AFRICA: 
Algeria 

153.798 

All  others 

26.0532 

3.152.070 

2,350.684 

'Includes  cork  waste,  shavings,  etc.,  prior  to  July  1.  1918.    sAustralla. 


CORK  INSULATION 


IMPORTS    OF    MERCHANDISE Continued 

FISCAL  YEAR  OF  1914— JUNE  30,  1913,   TO  JUNE  30,  1914 


IMPORTS  INTO 
UNITED  STATES 

Cork  Bark, 
or  Wood 
Unmanu- 
factured' 

Cork  Waste. 
Shavings,  etc. 

Cork  Discs. 

Wafers  and 

Washers 

All  Other 
Manufac- 
tures 

Dollars 

Pounds 

Dollars 

Pounds 

Dollars 

Dollars 

EUROPE: 

Belgium 

175 

Czechoslovakia 

Denmark 

Finland 

France 

Germany 

Netherlands.'.:  :!:;:'.^' 

7.479 
75,227 

14 

Poland  and  Danzig 

1,94V,618 

86,984 

Rumania 

Russia  in  Europe 

Spain 

i,42l'.894 

2,478,364 

Sweden 

United  Kingdom 

197 

33,399 

4 

AMERICA: 

Canada 

443 

Central  American  State^;. 

81 

Mexico 

South  American  Continent 

ASIA: 

China 

6 
26 

All  others 

AFRICA: 

266,435 

Morocco 

3.851.794 

1    

2.647.838 

FISCAL  YEAR  OF  1915— JUNE 

30,  1914,  TO  JUNE  30,  1915 

EUROPE: 

39 

Belgium 

Czechosliovakia.'.'..;^^. 

France 

Germany 

Netherlands.'.!:;:;.'.  ... 

17.000 
10.:<89 
47:884 

'°li 

Poland  and  Danzig 
Portugal 

1,595,945 

■  'eLQei' 

Russia  in  Europe 

■  "8'98'.4i5' 

1,923.371 



United  Kingdom 

3,698 

fiilo 

AMERICA: 

Canada 

Central  American  States. 



6 

Mexico ■ 

South  American  Continent 

18.647 

8 
2 

ASIA: 

China 

39' 

aIP  others .".':: ::::::.... 

AFRICA: 

Algeria 

Morocco 

All  others 

170.917 

Totals 

2.762.895 

2,024.059 

■Includes  cork  waste,  shavings,  etc.,  prior  to  July  1.  1918 


EXTENT  OF  CORK  INDUSTRY 


49 


IMPORTS    OF    MERCHANDISE Continued 

FISCAL  YEAR  OF  1916— JUNE  30,  1915,   TO  JUNE  30,  1916 


IMPORTS  INTO 

UNITED  STATES 

FROM 

Cork  Bark, 
or  Wood 
Unmanu- 
factured' 

Cork  Waste. 
Shavings,  etc. 

Cork  Discs. 

Wafers  and 

Washers 

All  Other 
Manufac- 
tures 

Dollars 

Pounds 

Dollars 

Pounds 

Dollars 

Dollars 

EUROPE:        _ 

?i-nnpp 

86.822 

5,679 
10 

1.985 
14 

r-erninnv 

2.671 

Norway 

Poland  and  Danzig 

i.noo,694 

83.680 

928.477 

847.224 

United  Kingdom 

2.545 
8.207 

lOJ 

2.231 

AMERICA: 

9> 

Cuba 

Mexico 

25 

190,?  66 

3 

West  Indies 

ASIA: 
China 

300 

All  others                  . .  •  • 

AFRICA: 

Algeria             

All  others                

941.243 

FISCAL  YEAR  OF  1917— JUNE 

30,  1916,   TO   JUNE  30.  1917 

EUROPE: 

56.396 

101.810 

3.633 

Italy     

6,326 

Netherlands 

Norway 

Poland  and  Danzig 

Portugal 

2.404.678 

105  647 

Rumania 

Russia  In  Europe 

1.058.574 

2.026,785 

Sweden 

United  Kingdom 

7.304 

3  094 

All  others    

AMERICA: 

Canada 

621 

16  799 

Central  American  States. . 

Cuba 

1.572 
10 
6 

1  111 
1,111 

Mexico 

South  A  merlcan  Continent 

ASIA: 

China 

Japan 

Alfothers 

AFRICA: 

Algeria         .... 

233.062 

Morocco 

All  others 

Totals 

3.870,389 

2  158  447 

■Includes  cork  waste,  shavings,  etc..  prior  to  July  1,  1918. 


so 


CORK  INSULATION 


IMPORTS    OF    MERCHANDISE Continued 

FISCAL   YEAR   OF  1918— JUNE   30,  1317,   TO   JUNE   30,   1918 


IMPORTS  INTO 

UNITED  STATES 

FROM 

Corli  Bark, 
or  Wood 
Unmanu- 
factured' 

Corli  Waste, 
Shavings,  etc. 

Cork  Discs, 

Wafers  and 

Washers 

All  Other 
Manufac- 
tures 

Dollars 

Pounds 

Dollars 

Pounds 

Dollars 

Dollars 

EUROPE: 

88,5i8 

7,486 

Germanv 

44,727 

72.548 

Netherlands 

Norway 

i. 754,750 

152,099 



946,373 

1,778,279 

Sweden 

United  Kingdom 

30,107 

1  474 

3.307 
163 

AMERICA: 

90 

ASIA: 
China 

AFRICA: 

197,352 

Totals 

3,061,827 

2,017,146 

CALENDAR   YEAR  1918 


EUROPE: 

Austria  and  Hungary    .  .  . 

Finland 

6,586 

1,415,529 

19,890 

9,491 

11,304 

8,007 

Tt^^v'^'*^ 

43,928 

72.548 

Portugal 

1,275,137 

9,558,460 

187.417 

118,282 

32,328 

90,463 

Spain 

459,087 

21,952,679 

373,112 

434,850 

395,211 

1,133,193 

United  Kingdom 

934 

All  others 

AMERICA: 

307 

' 

South  American  Continent 
West  Indies 

ASIA: 

26 

881 

AFRICA: 

112,832 

4.237,282 

52.033 

4,675 

3,110 

1,898,193 

37,163,950 

632,452 

567,298 

441,953 

1,306,333 

'Includes  cork  waste,  shavings,  etc.,  prior  to  July  1,  1918. 


EXTENT  OF  CORK  INDUSTRY 


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CORK  INSULATION 


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676,457 
25,864 
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s 

B 

i 

i 

0 

1 

i 

S  ■ 

1 

5 

io 

1^ 

1 

^ 

S 

•a 

1; 

1 

o 
1 

1 

1 

1 

i 

- 

e 

§ 

i 

h 

1^ 

00 

1 

3 

OtNCO 

i 

1 

1 

§ 

o 

^ 

2 

i 

1 

(2 

1 

i 

1 

1 

s 

1 

1 

Is 

o 

ti 
1 

. 

2  : 

3  • 

;  3 

c 

2 
I 

1^ 

^t 

5,: 

5 

5 

[ 

y 

p 

hP 

ii 

c 

:  = 

u 

III 

1 

c 

i 

i 
< 

1 

)J 

1 

c 

? 

1 

) 

i.l 

=  1 

J 

2 

< 

■1 

c 

j 

:    ^ 

< 

3< 

2 

EXTENT  OF  CORK  INDUSTRY 


57 


VALUE  OF  IMPORTS  OF  CORK  TO  THE  UNITED  STATES  (FISCAL  YEAR) 
Corkwood,  or  cork  bark,  and  manufactures  of  cork 


\T.AR 


VALUE 


1892 $  1,689,724.00 

1893 1,993,025.40 

1894 1,280,982.00 

1895 1,400,830.00 

1896 1,619,337.00 

1897 1,751,652.00 

1898 1,447,188.00 

1899 1,542,367.00 

1900 1,909,483.00 

1901 2,270,995.00 

1902 2,464,934.00 

1903 2,567,580.00 

1904 2,295,138.00 

1905 2,738,319.00 

14  Years $26,971,554.40 

Yearly  Average $  1,926,539.60 


YEAR  VALUE 

1906 $  3,313,306.00 

1907 4,063.982.00 

1908 4,249,006.00 

1909 3,042,190.00 

1910 4,771,391.00 

1911 6,609,813.00 

1912 5,588,734.00 

1913 5,502,754.00 

1914 6,499.632.00 

1915 4,786,954.00 

1916 4,076,127.00 

1917 5,028,836.00 

1918 5,028,973.00 

1918** 1,840,409.00 

1919* 5,740,910.00 

1920* 8,343,998.00 

1921* 3,418,256.00 

1922* 5,202,537.00 

1923* 5,067,902.00 

1924* 4,328,496.00 

19H  Years $96,604,206.00 

Yearly  Average $  4,954,061.88 

♦Calendar  Year. 

**July  1  to  Dec.  .31,  1918. 


58 


CORK  INSULATION 


IMPORTS  ENTERED  UNITED  STATES  FOR  CONSUMPTION 

FOR  FISCAL  YEAR.  1903 


CORK,  and  MANUFACTURES  OF: 

Rate 

of 
Duty 

Quantities 
Lbs. 

Values 
S 

Duties 

S 

Value 

Unft 

of 
Quan- 
tity 

$ 

Actual 
and 
Com- 
puted 
Ad 
Val- 
orem 
Rate 

Unmanufactured 

Free 

1 ,737.366.00 

Artificial  cork,  or  cork  substitutes,  mfd. 
from  cork  waste  or  granulated  cork  and 

Bark,  cut  in  squares,  cubes  or  quarters.  . 
Corks  (or  cork  stoppers) ; 

ii'  or  less  in  diam.  at  large  end 

Forrnfg.  in  bonded  whse.  and  export. 

8clb. 
25c  lb. 

4.00 
79.214.40 

2.00 
36,073.00 

0.32 
19,803.60 

.50 
.455 

16.00 
54.90 

Over  'i"  in  diam.  at  large  end 

1.5c  lb. 

1,409,507.16 

704,429.00 

211.426.08 

.50 

30.01 

Cork  disks   wafers  or  washers 

»/ii'  or  less  in  thickness 

For  mfg.  in  bonded  whse.  and  export. 

Cork  insulation;  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards. 

Cork  Tile 

Cork  Paper 

All  other  manufactures  wholly  or  in  chief 
value   of   cork   or   cork    bark,   or   of 
artificial    cork    or    cork    substitutes, 
granulated     or     ground     cork      not 

f       25% 
1  Remitted 

54.290.49 
795.00 

13.572.62 

■■.829 

25  00 

959.00 

Free 

1.737,366.00 



Dutiable 

795,589.49 

244,802.62 

30.77 

FOR  FISCAL  YEAR,  1904 


Unmanufactured 

Free 

1.484.405.00 

Manufactures  of 

Artificial  cork    or  cork  substitutes    mfd. 
from  cork  waste  or  granulated  cork  and 

Bark,  cut  in  squares,  cubes  or  quarters.  . 
Corks  (or  cork  stoppers) : 

Ji'  or  less  in  diam.  at  large  end 

8c  lb. 
25c  lb. 

1,580.00 
351.447.76 

212.00 
69.537.00 

126.40 
87,861.94 

.134 
.198 

59.62 
126.35 

Over  ?i'  in  diam.  at  large  end 

15c  lb. 

1.309.663.33 

640.569.51 

196.449.50 

.489 

30.67 

Cork  insulation:  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards. 

All  other  manufactures  wholly  or  in  chief 
value   of   cork   or   cork   bark,   or   of 
artificial    cork    or    cork    substitutes. 

/      25% 
\  Remitted 

67,289.00 
232.00 

16.822.25 

.792 

293.00 

Free 

1.484.405.00 

TOTALS 

Dutiable 

777.839.51 

301,260.09 

38.73 

EXTENT  OF  CORK  INDUSTRY 


59 


IMPORTS  ENTERED  UNITED  STATES  FOR  CONSUMPTION-Co/ianuerf 
FOR  FISCAL  YEAR,  1905 


CORK,  and  MANUFACTURES  OF: 

Rate 

of 
Duty 

Quantities 
Lbs. 

Values 

S 

Duties 

S 

Value 

U^^^t 

of 
Quan- 
tity 

S 

Actual 
and 
Com- 
puted 

vM 

% 

Unmanufactured 

Free 

1,728.743.00 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  mfcl 
from  cork  waste  or  granulated  cork  and 
n    o    p.  f 

Bark,  cut  in  squares,  cubes  or  quarters  . 
Corks  (or  cork  stoppers): 

%  '  or  less  in  diam.  at  large  end 

Sclb. 
25c  lb. 

340.00 
110,670.08 

167.00 
54,152.56 

27.20 
27,667.52 

.491 
.489 

16.29 
51.09 

Over  ^i  '  in  diam.  at  large  end 

15c  lb. 

1,633,226.97 

859,780.00 

244,984.06 

.526 

28.49 

'/ii'  or  less  in  thickness           

Over  3/i»'  in  thickness         

Cork  insulation:  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards. 

Cork  Tile                                      

Waste  shavings   or  refuse  of  all  kinds   . 

Cork  Paper                                     

All  other  manufactures  whoUy  or  in  chief 
value   of  cork  or  cork   bark,   or   of 
artificial    cork   or   cork   sub.stitutcs, 
granulated     or    ground     cork,     not 
specilically  provided  fnr 

25% 

38.298.55 

9.574.63 

25.00 

Free 

1,728,743.00 

TOTALS 

Dutiable 

952.398.11 

282.253.41 

29.64 

FOR    FISCAL   YEAR.  1906 


Unmanufactured 

Free 

1.837.354.00 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  nifd. 
from  cork  waste  or  granulated  cork  and 

Bark,  cut  in  squares,  cubes  or  quarters.  . 
Corks  (or  cork  stoppers) : 

H'  or  less  in  diam.  at  large  end 

8c  lb. 
25c  lb. 

5,993.00 
213.468.47 

1,289.00 
95,629.36 

479.44 
53.367.11 

.215 
.448 

37.19 
55.81 

Over  ?4"  in  diam.  at  large  end 

/  15c  lb. 
\Remitted 

1.939,781.00 
3.004.00 

1,279,974.50 
1,025.00 

290,967.17 

.660 

22.73 

Over  'h"  in  thickness 

Reciprocity  treaty  with  Cuba    .    .    . 

Cork  insulation:  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards, 
planks,  or  molded  forms  . 

Cork  Tile 

Waste   shavings    or  refuse  of  all  kinds 

Cork  Paper 

All  other  manufactures  wholly  or  in  chief 
value   of   cork    or   cork   bark,    or  of 
artificial    cork    or    cork    substitutes, 
granulated     or     ground     cork,     not 

25  T 

83.421.48 

20.855.37 

Free 

1.S37..354.00 

TOTALS 

Dutiable 

1.461. .3.39.34 

365.669.09 

25.02 

60 


CORK  INSULATION 


IMPORTS  ENTERED  UNITED  STATES  FOR  CONSUMPTION— CoM<int.ed 
FOR    FISCAL    YEAR.  1907 


CORK,  and  MANUFACTURES  OF: 

Hate 

of 
Duty 

Quantities 
Lbs. 

Values 
$ 

Duties 

$ 

Value 

Uni^t 

Quan- 
tity 

S 

Actual 
and 
Com- 
puted 
Ad 
Val- 

Rate 

Unmanufactured 

Free 

2.358.873.00 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  mfd. 
from  cork  waste  or  granulated  cork  and 

Bark,  cut  in  squares,  cubes  or  quarters . . 
Corks  (or  cork  stoppers) : 

h"  or  less  in  diarii.  at  large  end 

8c  lb. 
25o  lb. 

217.00 
91.591.00 

133.00 
54,413.00 

17.36 

22,897.75 

.613 
.594 

13.05 
42.08 

Over  %"  in  diam.  at  large  end 

/   15c  lb. 
\Remitted 

2,186,088.00 
1.191.50 

1,489.448.00 
494.50 

327.913.51 

.681 
.415 

22.02 

Cork  disks    wafers  or  washers 

',«'  or  less  in  thickness 

Cork  insulation;  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards, 

Cork  Tile     

Cork  Paper 

All  other  manufactures  wholly  or  in  chief 
value   of   cork   or   cork    bark,   or  of 
artificial    cork    or    cork    substitutes, 
granulated     or     ground     cork,     not 

25% 

159,541.50 

39.885.38 

25  00 

Free 

2.358,873.00 

Dutiable 

1,704,030.00 

390,714.00 



22.93 

FOR   FISCAL  YEAR,  1908 


Unmanufactured 

8c  lb. 
8c  lb. 

25c  lb. 

00,664.316.00 

3.395.00 
208.00 

49.483.25 

2,092,732.00 

1,638.00 
194.00 

29.863.00 

271.60 
16.64 

12.370.81 

.482 
.932 

.603 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  mfd. 
from  cork  waste  or  granulated  cork  and 
n.  o.  p.  f 

Bark,  cut  in  squares,  cubes  or  quarters .  . 

Corks  (or  cork  stoppers) : 

h"  or  less  in  diam.  at  large  end 

16.58 
8.57 

41.42 

Over  h"  in  diam.  at  large  end 

Reciprocity  treaty  with  Cuba 

1    15c  lb. 
\Remitted 
/   15c  lb.   \ 
lless  20%] 

2.435.154.91 

2.028.00 

450.00 

1.814.519.66 
938.00 
185.00 

365.273.24 
54.66 

.745 
.462 
.411 

20.13 
29.i8 

Cork  insulation;  whoUy  or  in  chief  value 
of  granulated  cork  in  slabs,  boards, 

AU  other  manufactures  wholly  or  in  chief 
value    of    cork    or   cork    bark,   or   of 
artificial    cork    or    cork    substitutes. 
granulated     or     ground     cork,     not 

25% 
/25%   lessl 
\     20%      j 

159,229.50 
123.00 

39.807.38 
24.60 

TOTALS 

Free 

60,664,316.00 

2,092,732.00 

Dutiable 

2.006,689.50 

417.818.27 

20.82 

EXTENT  OF  CORK  INDUSTRY 


61 


IMPORTS  ENTERED  UNITED  STATES  FOR  CONSUMPTION— Condnued 
FOR   FISCAL  YEAR,  1909 


FOR   FISCAL  YEAR,  1910 


CORK,  and  MANUFACTURES  OF: 

Rate 

of 
Duty 

Quantities 
Lbs. 

Values 

Duties 

S 

Value 
per 
Lnit 

of 
Quan- 
tity 

S 

Actual 
and 
Com- 
puted 
Ad 
Val- 

rut"e 

Unmanufactured 

Free 

78,330.391.00 

2,016,534.00 

.026 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  mfd. 
from  cork  waste  or  granulated  cork  and 

Bark,  cut  in  squares,  cubes  or  quarters .  . 
Corks  (or  cork  stoppers): 

4i'  or  less  in  diam.  at  large  end 

8c  lb. 
25c  lb. 

8.00 
52.762.00 

5.00 
31,362.00 

.64 
13,190.50 

.625 
.594 

12.80 
42.06 

Over  ?4'  in  diam.  at  large  end 

/   15c  lb. 
IRemitted 
/   15c  lb.    \ 
lless  207c/ 

1.163,580.50 

595.00 

1.051. OO 

885,536.00 
324.00 
434.00 

174,537.08 

.761 
.545 
.413 

19.71 

Reciprocity  treaty  with  Cuba 

126.12 

29.06 

Over  lit,"  in  thickness 

Cork  insulation;  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards. 

AU  other  manufactures  wholly  or  in  chief 
value   of   cork   or   cork    bark,    or   of 
artificial    cork    or    cork    substitutes, 
granulated     or     ground     cork,     not 

25% 

184.765.15 

46.191.29 

25.00 

Free 

78.130.391.00 

2,016.534.00 

.026 

Dutiable 

1.102,426.15 

234.045.63 

21.23 

Unmanufactured 

Cork  wood,  or  cork  bark 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  mfd. 
from  cork  waste  or  granulated  cork  and 
n.  o.  p.  f 

Bark,  cut  in  squares,  cubes  or  quarters 

Corks  (or  cork  stoppers) : 

ii"  or  less  in  diam.  at  large  end 

Free 

6c  Ib.i 
8c  lb. 

25c  lb. 

109,271,575.00 

183.00 
1,649.00 

41.699.00 

3,152,280.00 

103.00 
310.00 

29,820.00 

10.98 
131.92 

10,424.75 

.029 

.563 
.188 

.715 

10.66 
42.55 

34.96 

Over  H"  in  diam.  at  large  end 

/    15c  lb. 
IRemitted 
/   15c  lb.   1 

Hess  20%) 

1,709 .941. .55 
557.00 
710.00 

1,344,688.10 
236.00 
232.00 

256,491.24 

.786 
.424 
.327 

19.07 

Reciprocity  treaty  with  Cuba 

Cork  disks    wafers  or  washers 

85.20 

36.72 

Over  'u'  in  thickness 

or  mfg.  in  bonded  whse.  or  export . 

Cork  insulation:  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards. 

Cork  Tile    ' 

AU  other  manufactures  wholly  or  in  chief 
value   of   cork   or   cork   bark,    or   of 
artificial    cork    or    cork    substitutes. 

/     25%  > 
\     30% ' 

49,619.00 
126,611.00 

12.404.75 
37,983.30 

25.00 

specifically  provided  for 

30.00 

TOTALS 

Free 

109,271,575.00 

3,152,280.00 

.029 

Dutiable 

1,551.619.10 

317,532.14 

20.47 

'  Aug  6,  1909  to  June  30,  1910,  under  Act  of  I 


I  Aug.  5,  1909,  under  Act  of  1897. 


62 


CORK  INSULATION 


IMPORTS  ENTERED  UNITED  STATES  FOR  CONSUMPTION— Continued 
FOR   FISCAL  YEAR.  1911 


CORK,  and  MANUFACTURES  OF: 

Rate 

of 
Duty 

Quantities 
Lbs. 

Values 

S 

Duties 
$ 

Value 

U^^^t 

of 
Quan- 
tity 

S 

Actual 
and 
Com- 
puted 
Ad 
Val- 
orem 
Rate 
% 

Unmanufactured 

Cork  wood    or  cork  bark 

Free 

6c  lb. 
8c  lb. 

25c  lb. 

139,602,251.00 

1.00 
542.00 

30.771.00 

4,286,700.00 

1.00 
136.00 

23.296.00 

.06 
43.36 

7.692.76 

.031 

1.00 
.258 

.757 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  mfd. 
from  cork  waste  or  granulated  cork  and 

Bark,  cut  in  squares,  cubes  or  Quarters .  . 
Corks  (or  cork  stoppers) : 

}i'  or  less  in  diam.  at  large  end 

6.00 
31.88 

33.02 

Over  U"  in  diam.  at  large  end 

/   15o  lb. 
\  Remitted 

2.553.357.42 
614.00 

2,155,098.00 
389.00 

383,003.62 

.844 
.633 

17.77 

Vti'  or  less  in  thickness   . .              

For  mfg.  in  bonded  whse.  and  exporl 

Over  %'  in  thickness 

For  mfg.  in  bonded  whse.  and  export 

Cork  insulation;  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards. 

AU  other  manufactures  wholly  or  in  chief 
value   of   cork   or   cork   bark,   or   of 
artificial    cork    or    cork    substitutes, 
granulated     or     ground     cork,     not 
specifically  provided    "■■• 

30% 

210,825.21 

63,247.56 

30  00 

"^"^^^^ 

Free 

1.39.602.251.00 

4.286.760.00 

.031 

Dutiable 

2..389.745.21 

453,987.36 

19.00 

FOR   FISCAL  YEAR.  1912 


Unmanufactured 

Free 
6c  lb. 

118,432,309.00 
77.00 

3,247,086.00 
8.00 

4.62 

.027 
.104 

cork  ^°°'''^^,«^'f^,^f^^- -  f 

Artificial  cork,  or  cork  substitutes,  mfd. 
from  cork  waste  or  granulated  cork  and 

57.75 

Corks  (or  cork  stoppers) : 

25c  lb. 

21,998.58 

17.900.00 

5.499.63 

.814 

30.73 

:::::::::: 

Over  H'  in  diam.  at  large  end 

/   15c  lb. 
\  Remitted 

2,346,323.41 
693.00 

1,891,372.00 
341.00 

351,948.53 

.806 
.492 

18.61 

'/^'  or  less  in  thickness 

For  mfg   in  bonded  whse.  and  export 

Over  Mi"  in  thickness 

Cork  insulation;  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards. 

AU  other  manufactures  wholly  or  in  chief 
value   of   cork   or   cork   bark,   or  of 
artificial    cork    or    cork    substitutes. 
granulated     or     ground     cork,     not 

30% 

268,464.00 

80,539.20 

30  00 

Free 

118,432,309.00 

3,247,086.00 



.027 

■ 

Dutiable 

2,178.085.00 

437.991. 98i 

20.11 

EXTENT  OF  CORK  INDUSTRY 


IMPORTS  ENTERED  UNITED  STATES  FOR  CONSUMPTION— Coriiinwed 
FOR  FISCAL  YEAR,  1913 


63 


FOR   FISCAL  YEAR,  1914 


CORK  and  MANUFACTURES  OF: 

Rate 

of 
Duty 

Quantities 
Lbs. 

Values 
S 

Duties 

Value 

Um't 

of 
Quan- 
tity 

S 

Actual 
and 
Com- 
puted 
Ad 
Val- 

Ra™ 

Unmanufactured 

Free 

133,227,878.00 

3,152,070.00 

.024 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  mfd 
from  cork  waste  or  granulated  cork  and 

Bark,  cut  in  squares,  cubes  or  Quarters .  . 
Corks  (or  cork  stoppers) : 

h'  or  less  in  diam.  at  large  end 

For  tufg.  in  bonded  whse.  and  export. 

8clb. 
25c  lb. 

99.00 
20,635.50 

32.00 
15,637.00 

7.92 
5.158.88 

.323 
.758 

24.75 
32.99 

Reciprocity  treaty  with  Cuba 

Over  H"  in  diam.  at  large  end 

/   15c  lb. 
IRemitted 

2.490,194.73 
455.00 

2,171,955.00 
275.25 

373.529.21 

.872 
.605 

17.20 

Reciprocity  treaty  with  Cuba 

Cork  insulation:  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards, 
planks,  or  molded  forms 

Cork  Tile 

All  other  manufactures  wholly  or  in  chief 
value   of    cork   or   cork    bark,    or   of 
artificial    cork    or    cork    substitutes, 
granulated     or     ground     cork,     not 

30% 

157,250.00 

47.175.00 

Free 

133,227,878.00 

3.152,070.00 







Dutiable 

2.345,149.25 

425.871.01 



18  16 

Unmanufactured 

Cork  wood,  or  cork  bark 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  mfd 
from  cork  waste  or  granulated  cork  and 
n.  o.  p.  f 


Bark,  cut  in  squares,  cubes  or  quarters .  . 
Corks  (or  cork  stoppers) : 

?4*  or  less  in  diam.  at  large  end 

For  mfg.  in  bonded  whse.  and  export. 

Over  H"  in  diam.  at  large  end 

For  mfg.  in  bonded  whse.  and  export 


Reciprocity  treaty  with  Cuba 

I  Cork  disks,  wafers  or  washers 

lit"  or  less  in  thickness 

Over  '  u"  in  thickness 

For  mfg.  in  bonded  whse.  and  export 

Cork  insulation:  wholly  or  in  chief  value 

of  granulated  cork  in  slabs,  boards, 

planks,  or  molded  forms 

Cork  Tile 

Granulated  or  ground  cork 

Waste,  shavings,  or  refuse  of  all  kinds..  . 

Cork  Paper 

All  other  manufactures  wholly  or  in  chief 
value  of  cork  or  cork  bark,  or  of 
artificial  cork  or  cork  substitutes, 
granulated     or     ground     cork,     not 

specifically  provided  for 

Reciprocity  treaty  with  Cuba 


/  6c  lb.' 
1  3c  lb.« 
/  8c  lb.' 
1  4c  lb.» 
)2oclb.' 
\  15c  lb.' 
Free  ' 
/  15c  Ib.i 
1  12c  lb.» 
/  Free  ' 
1  Free' 
J  12c  less 
120%     ' 


15c  lb.» 
12c  lb.» 


Kc  lb.> 
Free  '' 


4.717.50 

82,805.00 

71.00 

548.452.25 

251.744.00 

378.00 

127.00 

146.00 


2,065,567.00 
19,469, 
120.00 


90,487,964.00 


151.00 

470.00 

343.00 

298.00 

3,831.00 

53.947.00 

53.00 

477,615.00 

192.517.00 

193.00 

80.00 


1,675,683.00 

9.443.00 

70.00 


67.84 
.179.38 
.429.75 


26.12 
22.76 
30.78 
23.04 


178,771,195.00  3,852,190.00 


387.00    507,422.60 


•Old  law,  July  1  to  Oct.  3,  1913      'New  Uw,  Oct.  4,  1913  to  June  30,  1914. 


64 


CORK  INSULATION 


IMPORTS  ENTERED  UNITED  STATES  FOR  CONSUMPTION— Continued 
FOR   FISCAL  YEAR,  191S 


FOR   FISCAL  YEAR,  1916 


CORK  and  MANUFACTURES  OF: 

Rate 

of 
Duty 

Quantities 
I.bs. 

Values 

$ 

Duties 
S 

Value 

U^n[t 

of 
Quan- 
tity 

S 

Actual 
and 
Com- 
puted 

orem 
Rate 

Unmanufactured 

Free 

3c  lb. 
4c  lb. 

15c  lb. 
Free 

24,897,803.00 

1,155.00 
6.125.00 

131,269.00 
734.00 

1  420  581.00 

320.00 
1.112.00 

82,576.00 
930.00 

.057 

.277 
.182 

.629 
1.257 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  mfd. 
from  cork  waste  or  granulated  cork  and 
n.  o.  p.  f 

Bark,  cut  in  squares,  cubes  or  quarters .  . 

Corks  (or  cork  stoppers) : 

Ji*  or  less  in  diam.  at  large  end 

For  mfg.  in  bonded  whse.  and  export. 

34.65 
245.00 

19,690.35 

10.83 
22.03 

23.85 

Over  U"  in  diam.  at  large  end 

For  mfg.  in  bonded  whse.  and  export 

12c  lb. 
Free 

194.721.00 
163.00 

166,705.60 
131.00 

23,366.52 

.856 
.805 

14.02 

Cork  disks   wafers  or  washers 

15c  lb. 
Free 

1,918,643.00 
126.00 

i.i66.'3l'6.66 
68.00 

287.7'96.45 

.605 
.54 



i2c  lb. 
Free 

7.841.00 
254.00 

4.996.00 
160.00 

940.92 

.638 
.63 

Cork  insulation:  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards, 
planks,  or  molded  forms 

Cork  Tile       .  .                               

Waste,  shavings,  or  refuse  of  all  kinds..  . 
Cork  Paper 

Free 
35% 

30% 

96,575,427.00 

1.334,262.00 
111.069.00 

41,466.00 

38.874.15 
12.439.80 

.014 
.35 

.301 

35  00 

AU  other  manufactures  wholly  or  in  chief 
value    of    cork    or   cork    bark,    or   of 
artificial    cork    or    cork    substitutes, 
granulated     or     ground     cork,     not 
specifically  provided  for 

30  00 

Free 

121,474,507.00 

2,756,132.00 

.023 

Dutiable 

1,568,560.00 

383,387.84 

24.44 

Unmanufactured 

Cork  wood   or  cork  bark 

Free 

32,866,700.00 

1.517.366.00 

.046 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  mfd. 
from  cork  waste  or  granulated  cork  and 

Corks  (or  cork  stoppers) : 

%'  or  less  in  diam.  at  large  end 

15c  lb. 

143,889.00 

86.681.00 

21.583.35 

.602 

24.90 

Over  U"  in  diam.  at  large  end 

For  mfg.  in  bonded  whse.  and  export 
Reciprocity  treaty  with  Cuba 

12c  lb. 

125.917.00 

84.065.00 

15,110.04 

.672 

17.97 

15c  lb. 

674,066.00 

464.931.00 

101.109.90 

.689 

12c  lb. 

21,710.00 

22.657.00 

2.605.20 

1.044 

Cork  insulation;  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards, 

Mclb. 

956,979.00 

39,651.00 

2.392.46 

.041 

Cork  Tile                                 .  .    .  . 

Waste,  shavings,  or  refuse  of  all  kinds..  . 
Cork  Paper 

Free 
35% 

30% 

122,577.224.00 

1,617,518.00 
136.615.00 

43,668.00 

'  '47.815.25 
13.100.40 

.013 

35  00 

All  other  manufactures  wholLv  or  in  chief 
value   of   cork   or   cork   bark,    or   of 
artificial    cork    or    cork    substitutes, 
granulated     or     ground     cork,     not 

30.00 

Free 

155.443.924.00 

3,134,884.00 

.021 



Dutiable 

878,268.00 

203.716.60 

23.20 

EXTENT  OF  CORK  INDUSTRY 


65 


IMPORTS  ENTERED  UNITED  STATES  FOR  CONSUMPTION— Conhnwed 
FOR  FISCAL  YEAR,  1917 


CORK  and  MANUFACTURES  OF: 

Rate 

of 
Duty 

Quantities 
Lbs. 

Values 

S 

Duties 

Value 

of 
Quan- 
tity 

S 

Actual 
and 
Com- 
puted 
Ad 
Val- 

fUt" 

Unmanufactured 

Free 

40,273,005.00 

2,125,633.00 

.055 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  mfd. 
from  cork  waste  or  graniJated  cork  and 

Bark,  cut  in  squares,  cubes  or  quarters 
Corks  (or  cork  stoppers) : 

h'  or  less  in  diam.  at  large  end 

4c  lb. 
15c  lb. 

573.00 
147,394.00 

116.00 
96,289.00 

22.92 
22,109.10 

.202 
.652 

19.76 
22.96 

Over  U"  in  diam.  at  large  end 

12c  lb. 

290,156.00 

178,872.00 

34.818.72 

.458 

19.47 

Cork  disks,  wafers  or  washers 

15c  lb. 

2.759.446.00 

1.933,621.00 

413.916.90 

.616 

For  mfg.  in  bonded  whae.  and  export 

Reciprocity  treaty  with  Cuba 

Over  'i,'  in  thickness 

Reciprocity  treaty  with  Cuba 

Cork  insulation:  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards, 

/    15c  lb.   \ 
\less  20%) 

12c  lb. 
/   12c  lb.   I 
lless  20%; 

J^ic  lb. 

1,006.00 

53,186.00 

877.00 

4.038.372.00 

1.111.00 

37.721.00 

889.00 

181.698.00 

120.72 

6.382.32 

84.19 

10,095.93 

1.104 
.711 
1.014 

.045 

10.87 
16.92 
9.47 

Waste,  shavings,  or  refuse  of  all  kinds..  . 

Free 
35% 

30% 

120.677,624.00 

1,743.184.00 
138,214.00 

58.273.00 

■  ■48,374.90 
17,481.90 

.015 

All  other  manufactures  wholly  or  in  chief 
value   of   cork   or   cork    bark,    or   of 
artificial    cork    or    cork    substitutes, 
granulated     or     ground     cork,      not 

30  00 

■■       TOTALS 

Free 

160,950,629.00 

3.868,817.00 

.024 

Dutiable 

2,626,804.00 

553,407.6(1 

21.07 

FOR   FISCAL  YEAR.  1918 


Unmanufactured 

Free 

3c  lb. 
4c  lb. 

15c  lb. 

30.750.497.00 

100.00 
5.00 

177.292.00 

1,479.072.00 

25.00 
1.00 

70,233.00 

3.00 
.20 

26,593.80 

.048 

.25 
.20 

.399 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  mfd. 
from  cork  waste  or  granulated  cork  and 

Bark,  cut  in  squares,  cubes  or  quarters .  . 
Corks  (or  cork  stoppers) : 

H'  or  less  in  diam.  at  large  end 

12.00 
20.00 

37.86 

Over  'i'  in  diam.  at  large  end 

For  mfg.  in  bonded  whse.  and  export 

12c  lb. 

189.585.00 

128,145.00 

22.750.20 

.675 

17.75 

'/ji'  or  less  in  thickness 

15c  lb. 

2,258.233.00 

1.401,694.00 

338.734.95 

.62 

24  17 

For  mfg.  in  bonded  whse.  and  export 

12c  lb. 

57.785.00 

44,157.00 

6.934.20 

.762 

15  70 

For  mfg.  in  bonded  whse.  and  export 

Cork  insulation:  wholly  or  in  chief  value 
of  granulated  cork   in  slabs,  boards, 
planks,  or  molded  forms 

Mc  lb. 

3,771,294.00 

181.402.00 

9,428.23 

.048 

5.20 

Waste   shavings   or  refuse  of  all  kinds..  . 

Free 
35% 

30% 

95.051.164.00 

1,582,755.00 
107,462.00 

44.403.00 

37.611.70 
13.320.90 

.017 

All  other  manufactures  wholly  or  in  chief 
value   of   cork   or   cork   bark,   or   of 
artificial    cork    or    cork    substitutes, 
granulated     or     ground     cork,     not 

30.00 

™^^^^ 

Free 

125,801,661.00 

3,061,827.00 

.024 

Dutiable 

1,977,522.00 

455,377.18 

23.03 

66 


CORK  INSULATION 


IMPORTS  ENTERED  UNITED  STATES  FOR  CONSUMPTION— ConUnwed 
FOR   CALENDAR   YEAR,  1918 


CORK  and  MANUFACTURES  OF: 

Rate 

of 
Duty 

Quantities 
Lbs. 

Values 

Duties 

S 

Value 
per 
Unit 

of 
Quan- 
tity 

s 

Actual 
and 
Com- 
puted 
Ad 
Val- 
orem 
Rate 
% 

Unmanufactured 

Free 

22,560,059.00 

1,297,636.00 

.058 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  mfcl. 
from  cork  waste  or  granulated  cork  and 
n.  o.  p.  f 

Bark,  cut  in  squares,  cubes  or  quarters 
Corka  (or  cork  stoppers) : 

H"  or  less  in  diam.  at  large  end 

For  mfg.  in  bonded  whse.  and  export. 

4c  lb. 
15c  lb. 

5.00 
64,556.00 

1.00 
20,605.00 

9,683.40 

.20 
.319 

20.00 
47.00 

Over  H"  in  diam.  at  large  end 

For  mfg.  in  bonded  whse.  and  export 

12c  lb. 

101,021.00 

72.426.00 

12,122.52 

.716 

16.74 

15c  lb. 

2,010,408.00 

1.316,590.00 

301.561.20 

.655 

For  mfg.  in  bonded  whse.  and  export 

Over  V  in  thickness 

12o  lb. 

71,112.00 

46.495.00 

8.533.44 

.654 

18.35 

For  mfg.  in  bonded  whse.  and  export 

Cork  insulation:  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards. 

He  lb. 

1,349,570.00 

63.704.00 

3.373.92 

.047 

Cork  Tile 

Waste,  .shavings,  or  refuse  of  all  kinds..  . 

Free 
35% 

30% 

72,421,740.00 

1.233.009.00 
116.665.00 

32,546.00 

■40.832.75 
9.763.80 

.017 

All  other  manufactures  wholly  or  in  chief 
value   of   cork    or    cork    bark,    or    of 
artificial    cork    or    cork    substitutes, 
granulated     or     ground     cork,     not 

Free 

94,981,799.00 

2,530,645.00 

.027 

Dutiable 

1.669.032.00 

385,871.23 

23.12 

FOR 

CALENDAR   YEAR,  1919 

Unnnanufactured 

Free 

3c  lb. 
4c  lb. 

15c  lb. 

28.286.942.00 

175,331.00 
6,135.00 

76,397.00 

1,802.506.00 

116,505.00 
3,129.00 

65.150.00 

5,259.93 
.  .  .    245.40 

11,459.55 

.064 

.666 
.51 

.853 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  mfd. 
from  cork  waste  or  granulated  cork  and 
n   0.  p.  f 

Bark,  cut  in  squares,  cubes  or  quarters  .  . 

Corks  (or  cork  stoppers) : 

Jj'  or  less  in  diam.  at  large  end 

4.51 
7.84 

17.59 

Over  h"  in  diam.  at  large  end 

For  mfg.  in  bonded  whse.  and  export 

12c  lb. 

73,728.00 

59,966.00 

8,847.36 

.815 

14.74 

15c  lb. 

/   15c  lb.   1 

lless  20%/ 

12c  lb. 

766.947.00 
24,106.00 
12,651.00 

452,331.00 
18,617.00 
8,991.00 

115,042.05 
2,892.72 
1,518.12 

.589 
.773 
.714 

Reciprocity  treaty  with  Cuba 

15.54 
16  88 

For  mfg.  in  bonded  whse.  and  export 

Cork  insulation;  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards. 

Mc  lb. 

5,719.668.00 

411,472.00 

14,299.17 

.072 

Waste,  shavings,  or  refuse  of  all  kinds..  . 

Free 
35% 

30% 

131.641.699.00 

2,558,556.00 
101,569.00 

51.286.00 

■  ■35,549.15 
15,385.80 

.019 

All  other  manufactures  wholly  or  in  chief 
value   of   cork   or   cork   bark,   or   of 
artificial    cork    or    cork    substitutes, 
granulated     or     ground     cork,     not 

30.00 

Free 

159.928.641.00 

4,361,062.00 

.027 

Dutiable 

1  1,289,016.00 

210.499.25 

EXTENT  OF  CORK  INDUSTRY 


67 


IMPORTS  ENTERED  UNITED  STATES  FOR  CONSUMPTION— Coniinwed 
FOR   CALENDAR   YEAR,  1920 


CORK  and  MANUFACTURES  OF: 

Rate 

of 
Duty 

Quantities 

Lbs. 

Values 
S 

Duties 
S 

Value 

Unit 

of 
Quan- 
tity 

$ 

Actual 
and 
Com- 
puted 
Ad 
Val- 

R^at^ 

Unmanufactured 

Free 

3c  lb. 
4c  lb. 

15e  lb. 

53,927,976.00 

6.00 
1,387.00 

103,961.00 

2,596,600.00 

1.00 
403.00 

88,509.00 

.18 
55.48 

15,594.15 

.048 

.167 
.291 

.85 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  mfd. 
from  cork  waste  or  granulated  cork  and 
n.  o.  p.  f 

Bark,  cut  in  squares,  cubes  or  quarters.  . 

Corks  (or  cork  stoppers) : 

h'  or  less  in  diam.  at  large  end 

18.00 
13.77 

17.62 

;:::::::::: 

Over  U"  in  diam.  at  large  end 

Reciprocity  treaty  with  Cuba 

12c  lb. 
/   12c  lb.   1 
lless  20%/ 

67.790.00 
176.00 

39,430.00 
74.00 

8,134.80 
16.90 

.58 
.421 

20.63 
22.84 

ISc  lb. 

1,382,697.66 

905.429.00 

267,404.55 

.065 

For  mfg.  in  bonded  whse.  and  export 

Over  'u'  in  thickness 

12c  lb. 

11.764.00 

6,736.00 

1.411.68 

.572 

20.96 

Cork  insulation:  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards, 

Ho  lb. 

9,000,101.00 

771,123.00 

22,500.25 

.086 

2  92 

Waste,  shavings,  or  refuse  of  all  kinds..  . 
Cork  Paper 

Free 

35  7o 

30% 

169,549,364.00 

3,741,730.00 
62,560.00 

94,938.00 

■  ■21,896.00 
28,481.40 

.022 



AU  other  manufactures  wholly  or  in  chief 
value   of   cork   or   cork   bark,   or   of 
artificial    cork    or    cork    substitutes, 
granulated     or     ground     cork,     not 

Reciprocity  treaty  with  Cuba.  .  .  . 

TOTALS 

Free 

223,477,340.00 

6,338,330.00 

.028 

Dutiable 

1,969,203.00 

305,495.39 

FOR   CALENDAR   YEAR.  1921 


Unmanufactured 

Free 

3c  lb. 
4c  lb. 

15c  lb. 

22.147.868.00 

220.00 
8.00 

72.718.00 

959,947.00 

41.00 
2.00 

59,451.00 

6.60 
.32 

10,907.70 

.044 

.187 
.25 

.818 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  mfd. 
from  cork  waste  or  granulated  cork  and 

Bark,  cut  in  squares,  cubes  or  quarters .  . 
Corks  (or  cork  stoppers) : 

H"  or  less  in  diam.  at  large  end 

16.10 
16.00 

18.35 

Over  ?4'  in  diam.  at  large  end 

For  mfg.  in  bonded  whse.  and  export 

12c  lb. 

84.519.00 

42.846.00 

10,142.28 

.506 

23.66 

Cork  disks    wafers  or  washers 

lit'  or  less  in  thickness 

15c  lb. 

509.765.00 

380,069.00 

76,464.75 

.748 

20  12 

12c  lb. 

29.205.00 

22,918.00 

3,504.60 

.792 

Cork  insulation:  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards 

Mclb. 

8,971,847.00 

517,772.00 

22,429.62 

.058 

Waste,  shavings,  or  refuse  of  all  kinds..  . 

Free 
35% 

30% 

88,255,141.00 

1.397,212.00 
25,462.00 

51,893.00 

■  ■8,911.70 
15,567.90 

.016 

AU  other  manufactures  wholly  or  in  chief 
value   of   cork   or   cork    bark,   or   of 
artificial    cork    or    cork    substitutes, 
granulated     or     ground     cork,     not 

30.00 

Free 

110,403,009.00 

2,357,159.00 

.021 

•  Dutiable 

1,100.454.00 

147.935.47 

08 


CORK  INSULATION 


IMPORTS  ENTERED  UNITED  STATES  FOR  CONSUMPTION— Conhraued 
FOR   CALENDAR  YEAR,  1922 


CORK  and  MANUFACTURES  OF: 

Rate 

of 
Duty 

Quantities 
Lbs. 

Values 
$ 

Duties 
S 

Value 

U^n^t 

of 
Quan- 
tity 

$ 

Actual 

Com- 
puted 
Ad 
Val- 

Rat" 

Unmanufactured 

Cork  wood   or  cork  bark 

Free 

60.116.486.00 

1.560.059.00 

.026 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  mfd. 
from  cork  waste  or  granulated  cork  and 

Bark,  cut  in  SQuares,  cubes  or  quarters . 
Corks  (or  cork  stoppers) : 

H"  or  less  in  diam.  at  large  end 

4c  lb.' 

/  15c  lb.' 
I  25c  lb.» 

1.174.00 

93.528.00 
24.051.00 

105.00 

59,804.00 
20.551.00 

46.96 

14,029.20 
6,012.75 

.64 
.838 

44.72 

23.46 
29.25 

Over  h"  in  diam.  at  large  end 

/  12c  lb.' 
I  20c  lb.' 

61.048.00 
24.042.00 

28.464.00 
22,601.00 

7.325.76 
4.808.40 

.465 
.94 

25.74 
21.27 

'/if"  or  less  in  thickness 

/  15c  lb.' 
I  25c  lb.' 

260.109.00 
33.496.00 

144,750.66 
15.234.00 

39.016.35 
8.374.00 

.556 
.455 

26.95 
54.97 

/  12c  lb.' 
\  20c  lb.' 

/  He  lb.' 
\  30%     ' 
25%  ' 
Free 
/     35%  ' 
\     30%  ' 

/     30%  ' 
\     30%  • 

18,014.00 
3,835.00 

13.040,492.00 

1.577.708.00 

25.00 

184,541,464.00 

13.338.00 
2.497.00 

776.655.00 

91.002.00 

9.00 

2.484,321.00 

15,185.00 

1,411.00 

67,397.00 
24.278.00 

2.161.68 
767.00 

32.601.23 

27.300.60 

2.25 

'5,'3i4.75 
423.30 

20,219.10 
7.283.40 

.743 
.65 

.06 
.058 
.36 
.014 

1.32 
".196 

16.21 
30.71 

4.20 
30.00 

Cork  insulation;  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,    boards 

Granulated  or  ground  cork 

Waste,  shavings,  or  refuse  of  aU  kinds..  . 

25.00 
35.66 

1.070.00 

All  other  manufactures  wholly  or  in  chief 
value   of    cork   or   cork   bark,   or   of 
artificial    cork    or    cork    substitutes, 
granulated     or     ground     cork,     not 

30.00 

123.780.00 

30.00 

Reciprocity  treaty  with  Cuba 

Free 

244,657.950.00 

4,044,380.00 

.017 

Dutiable 

1,283.281.00 

175.686.73 

FOR   CALENDAR  YEAR,  1923 


Unmanufactured 

Free 

/    Oclb.-i 

\  lOc  lb.« 

8o  lb. 

25c  lb. 

62.975.549.00 

590.00 
201.00 
799.00 

123.153.00 

1,776.417.00 

17i:00 
218.00 

163,001.00 

35.40 
20.10 
63.92 

30.788.25 

.028 

.521 
.851 
.273 

1.324 

Manufactures  of 

Artificial  cork,  or  cork  substitutes,  mfd. 
from  cork  waste  or  granulated  cork  and 
n.  o.  p.  f 

Bark,  cut  in  squares,  cubes  or  quarters .  . 

Corks  (or  cork  stoppers) : 

H"  or  less  in  diam.  at  large  end 

11.49 
11.75 
29.32 

18.89 

Over  W  in  diam.  at  large  end 

20c  lb. 

113.301.00 

112.563.00 

22,660.20 

.994 

20.13 

25e  lb. 

315.333.00 

209.084.00 

78.833.25 

.664 

37  70 

/  20c  lb.» 
\  10c  lb.« 

65.540.00 
123.00 

53.523.00 
48.00 

11.108.00 
12.30 

.964 
.391 

20.75 
25.63 

Cork  insulation;  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards, 
planks   or  molded  forms 

30% 
30% 
25% 
Free 
30% 

30% 

13.976.878.00 

16,800.00 

11,273.00 

164.571,128.00 

6,977.00 

1,176,886.00 

496.133.00 

1,875.00 

242.00 

1.951,143.00 

6,211.00 

181,223.00 

148.839.90 
562.50 
60.50 

■   1,863.30 
54,366.90 

.034 
.112 
.022 
.012 
.891 

.154 

30  00 

Cork  Tile 

30  00 

25  00 

Waste   shavings,  or  refuse  of  all  kinds..  . 

30  66 

All  other  manufactures  wholly  or  in  chief 
value   of   cork   or   cork    bark,   or  of 
artificial    cork    or    cork    substitutes, 
granulated     or     ground     cork      not 

30  00 

Free 

227.546,677.00 

3.727,560.00 

.016 

Dutiable 

15,797,854.00 

1,224,600.00 

349,214.52 

.078 

•Old  law.  Jan.    1   to   Sept.   21.   Act  of  Oct.  3.    1913.   and  Emergency  Tariff  Act  of  May  27.  1921. 
law.   Sept.  22  to  Dec.  31.      'Made  from  natural  cork  bark.      *Made  from  Artificial  or  Composition 
•In  the  rough,  not  further  advanced  than  slabs,  blocks  or  planks.      'In  rods  or  sticks  suitable  for  the  r 
facture  of  disks,  wafers,  or  washers. 


EXTENT  OF  CORK  INDUSTRY 


IMPORTS  ENTERED  UNITED  STATES  FOR  CONSUMPTION— Conh-»ue<2 
FOR   CALENDAR   YEAR,  1924 


CORK  and  MANUFACTURES  OF: 

Rate 

of 
Duty 

Quantities 
Lbs. 

Values 
S 

Duties 

S 

Value 

ty.![t 

of 
Quan- 
tity 

S 

Actual 
and 
Com- 
puted 
Ad 
Val- 

R'^^te 

% 

Unmanufactured 

Free 

fie  lh.» 
8c  lb. 

/25c    lb.' 
\12;clb.' 

61,556,348.00 

1,025.00 
804.00 

159,781.00 
138.00 

1,234.424.00 

201.00 
267.00 

233,280.00 
70.00 

61.50 
64.32 

39.945.25 
17.25 

03 

.196 
.332 

.146 
.508 

Manufactures  of 

Artificial  cork    or  corls;  substitutes,  mfd. 
from  cork  waste  or  granulated  cork  and 

Bark,  cut  in  squares,  cubes  or  quarters .  . 
Corks  (or  cork  stoppers) : 

U'  or  less  in  diam.  at  large  end 

30.60 
24.09 

17.12 
24.64 

Over  U"  in  diam.  at  large  end 

/20c  lb.' 
\  10c  lb.' 

113,886.00 
25.00 

156.051.00 
16.00 

22.777.20 
2.50 

1.37 
.64 

14.60 
15.63 

'is'  or  less  in  thickness 

25c  lb.' 

317,761.00 

275.100.00 

79.440.25 

.855 

28  88 

For  mfg.  in  bonded  whse.  and  export 

Over  'is"  in  thickness 

20c  lb." 

80,613.00 

110,451.00 

16.122.60 

1.37 

14  60 

For  rafg.  in  bonded  whse.  and  export 

Reciprocity  treaty  with  Cuba 

Cork  insulation:  wholly  or  in  chief  value 
of  granulated  cork  in  slabs,  boards. 

/  20c  lb.     1 
\less  207c  1 

30% 

122.00 
21.363.488.00 

75.00 
781.568.00 

19.52 
234.470.40 

.eis 

.037 

26.03 

25% 
Free 
30% 

608.221.00 

131.048,779.00 

38.00 

4.099.843.00 

8,097.00 

1,377.714.00 

24.00 

273.867.00 

2.174.25 

7'.20 

82,160.10 

.014 
.011 
.632 

.067 

Waste,  shavings,  or  refuse  of  all  kinds..  . 

All  other  manufactures  whoUy  or  in  chief 
value   of   cork    or   cork    bark,    or   of 
artificial    cork    or    cork    substitutes, 
granulated     or     ground     cork,     not 

30.00 

Free 

192,005,127.00 

2.612,138.00 

.014 

Dutiable 

26,745,745.00 

1,839,067.00 

477,202.34 

.07 

or  compositioD  cork.      'In  the  rough,  not  further 


70 


CORK  INSULATION 


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CORK  INSULATION 
Part  II— The  Study  of  Heat 


CHAPTER  VII. 
HEAT,  TEMPERATURE  AND  THERMAL  EXPANSION. 

31. — Molecular  Theory  of  Heat. — The  sensation  of  heat  is 
normally  recorded  by  the  sense  of  touch  if  heat  is  transferred 
from  a  gas,  liquid  or  solid  to  the  human  body ;  and  the  sensa- 
tion of  cold  results  from  a  transfer  of  heat  from  the  human 
body  to  a  gas,  liquid  or  solid.  For  the  purpose  of  our  study 
of  heat,  it  will  be  best  to  think  principally  in  terms  of  heat, 
rather  than  in  terms  of  cold. 

For  many  centuries  it  was  generally  believed  that  heat 
was  an  invisible,  elastic  and  weightless  fluid,  termed  caloric, 
which  was  responsible  for  all  thermal  phenomena  by  entering 
gases,  liquids  and  solids  in  some  mysterious  or  hypothetical 
manner,  possibly  even  combining  temporarily  with  them.  It 
was  not  until  about  the  beginning  of  the  nineteenth  century 
that  the  materialistic  conception  of  heat  was  rather  definitely 
disproven  by  certain  experiments  conducted  by  Count  Rum- 
ford  (Benjamin  Thompson)  (1753-1814),  an  American  phi- 
losopher who  made  important  contributions  to  physics  and 
agriculture  and  later  become  adviser  to  the  King  of  Bavaria, 
and  by  Sir  Humphry  Davy  (1778-1829),  an  English  chemist. 
But  it  remained  for  James  Prescott  Joule  (1818-1889),  an 
English  physicist,  to  prove,  about  the  middle  of  the  nineteenth 
century,  that  a  definite  amount  of  mechanical  work  is  equiv- 
alent to  a  definite  amount  of  heat,  when  it  soon  became  evi- 
dent that  heat  is  a  form  of  energy. 

The  kinetic  theory  of  heat  holds,  briefly,  that  the  molecules 
of  a  body  have  a  certain  amount  of  independent,  though  irreg- 
ular, motion,  and  any  increase  in  the  energy  of  that  motion 
manifests  itself  in  the  body  becoming  warmer,  and  any  de- 

71 


72  CORK  INSULATION 

crease  by  its  becoming  cooler,   heat,   in   a   word,   being  con- 
sidered as  kinetic  energy  of  molecular  motion. 

The  molecular  theory  of  heat  goes  one  step  farther  and  holds 
that  heat  is  in  part  the  kinetic  energy  of  molecular  motion, 
as  just  elaborated,  and  in  remaining  part  the  potential  energy 
of  molecular  arrangement.  The  molecular  theory  ef  heat  per- 
mits a  readier  grasp  of  the  facts  concerning  heat  than  seems 
otherwise  possible,  and  for  that  reason  is  today  generally 
accepted. 

32. — Temperature. — It  is  a  mere  matter  of  observation  that 
if  .several  spoonfuls  of  ice  water  are  added  to  a  cup  of  hot 
cofifee,  the  entire  contents  of  the  cup  quickly  become  cooler, 
the  heat  flowing  from  the  hot  cofTee  to  the  cold  water  until  a 
quiescent  state,  in  which  there  is  no  tendency  to  further 
change  of  any  kind,  known  as  thermal  equilihrmm,  is  established 
between  them.  If  the  same  cup  is  then  allowed  to  stand  in  a 
closed  room,  without  outside  interference  or  disturbance  of 
any  kind,  the  heat  will  flow  from  the  coffee  to  the  cup  to  the 
table  to  the  air  of  the  room  until  all  substances  in  the  room 
settle  to  a  state  of  thermal  equilibrium ;  and  when  a  number 
of  bodies  have  settled  to  such  a  common  state  of  thermal 
equilibrium  they  are  said  to  have  the  same  temperature. 

The  transfer  of  heat  is  alv/ays  from  the  body  of  higher 
temperature  to  the  one  of  lower  temperature  until  those  tem- 
peratures are  exactly  the  same,  or  until  thermal  equilibrium 
is  established  between  them.  Temperature  may  be  thought  of 
as  the  thermal  condition  of  a  body,  or  the  measure  of  the  degree 
of  hotness;  but  it  must  not  be  confused  with  quantity  of  heat. 
A  cup  of  coffee  may  be  at  exactly  the  same  temperature  as  the 
water  in  a  l,0(X)-gallon  hot  water  tank,  yet  the  tank  contains  a 
vastly  greater  quantity  of  heat  than  the  cup,  owing  to  the  vastly 
greater  quantity  of  liquid  held  by  the  tank. 

When  a  substance  is  hot  its  temperature  is  said  to  be 
high,  and  when  cold  its  temperature  is  said  to  be  low. 

33. — Dissipation  of  Energy. — Every  actual  case  of  motion 
is  attended  by  friction  and/or  collision  on  the  part  of  the  mov- 
ing body,  and  that  part  of  its  energy  not  employed  in  doing 
work  is  thus  dissipated.  This  dissipation  of  energy  is  always 
accompanied  by  the  generation  of  heat,  or,  stated  another  way, 


HEAT  AND  THERMAL  EXPANSION 


71 


such  dissipation  of  energy  is  the  conversion  of  mechanical 
energy  into  heat.  A  familiar  example  of  the  generation  of 
heat  by  the  dissipation  of  energy  is  the  stamping  of  one's  feet 
in  cold  weather  to  make  them  warm.  Another  example  of 
the  dissipation  of  energy  is  furnished  by  the  change  in  po- 
tential energy  resulting  from  the  drop  in  temperature  of 
superheated  steam  caused  by  the  radiation  or  loss  of  heat 
from  uninsulated  boiler  surfaces  or  steam  pipe  lines. 

34. — Effects  of  Heat. — The  heating  of  a  substance,  by  the 
dissipation  of  energy,  by  contact  with  a  hot  body,  or  by  any 
other  means,  may  produce  these  effects: 

(a)  Rise  in  temperature. 

(b)  Meltage  or  vaporization. 

(c)  Contraction   or   expansion. 

(d)  Dissociation,  if  a  chemical  compound. 

(e)  Exhibition  of  electrical  phenomena. 

35. — Thermometers. — The  most  convenient  instrument  to 
measure  temperature,  rise  and  fall,  is  a  mercury  thermometer, 

A  P  B 


Fahrenheit     3 

2 

F 

2 

12 

Centigrade 

0 

C 

1 

00 

Jieaumur 

0 

It 

80 

FIG.    29.— COMPARISON    OF    THREE    TYPES    OF   THERMOMETERS— (A) 

FREEZING    POINT;    (B)    BOILING    POINT;     (P)    THERMOMETER 

READING. 

which  employs  a  glass  tube  of  uniform  bore  having  a  blown 
bulb  on  one  end.  A  part  of  the  air  contained  in  the  bulb 
and  tube  is  expelled  by  expansion  resulting  from  heating, 
and  the  open  end  of  the  tube  is  then  immersed  in  pure  mer- 
cury. As  the  tube  cools  the  air  within  it  cools  and  contracts, 
and  atmospheric  pressure  relieves  the  condition  by  forcing 
mercury  into  the  open  end  of  the  tube.  This  method  is  used 
to  fill  the  bulb  completely  and  the  tube  only  to  a  point  where 
the  lowest  temperature  the  thermometer  is  to  measure  is  to 
be  indicated  on  the  tube  or  glass  stem.  Then,  after  heat 
applied  to  the  the  bulb  has  raised  the  mercury  to  the  very 
top,  the  open  end  of  the  tube  is  sealed  in  a  blowpipe  flame.  As 


74  CORK  INSULATION 

the  tube  and  mercury  cool,  the  contracting  mercury  moves 
clown  the  glass  stem,  leaving  a  vacuum  at  the  top  of  the 
tube. 

Since  the  temperature  of  melting  ice  and  that  of  steam, 
under  a  constant  pressure,  have  been  found  by  very  careful 
experiment  to  be  invariable,  their  respective  temperatures  at 
a  pressure  of  76  centimeters  (29  922  inches)  of  mercury  have 
been  selected  as  the  fixed  points  on  a  thermometer.  The  in- 
strument is  placed  in  an  ice  bath  and  the  freezing  point  is  marked 
on  the  tube;  it  is  then  enveloped  in  steam  and  the  boiling  point 
is  similarly  recorded,  proper  corrections  being  made  to  com- 
pensate for  any  pressure  different  from  76  cm. 

The  number  of  spaces,  or  degrees,  into  which  the  distance 
between  the  fixed  points  is  divided  has  been  subject  to  much 
discretion,  but  the  three  scales  most  used  are  the  Fahrenheit,  the 
Centigrade  and  the  Reaumur.  Gabriel  Daniel  Fahrenheit  (1686- 
1736),  a  German  physicist,  introduced  the  Fahrenheit  scale 
about  1714,  and  it  is  today  in  common  use  in  all  English- 
speaking  countries  in  spite  of  the  unreasonableness  of  desig- 
nating the  freezing  point  as  32°,  the  boiling  point  as  212° 
and  dividing  the  scale  between  into  180  equal  parts.  Rene 
Antoine  Ferchault  de  Reaumur  (1638-1757),  a  French  physic- 
ist, devised  the  Reaumur  scale  in  1731,  which  is  today  in 
common  use  in  the  households  of  Europe,  the  zero  point 
corresponding  to  the  temperature  of  melting  ice  and  80°  to 
the  temperature  of  boiling  water.  Some  erroneously  credit 
Anders  Celsius  (1701-1744),  a  Swedish  astronomer,  with  the 
Centigrade  scale,  which  fixes  zero  as  the  temperature  of 
melting  ice  and  100  as  the  temperature  of  boiling  water,  but 
the  Celsius  scale  (now  in  disuse  entirely)  reversed  these 
fixed  points  and  designated  100  as  the  temperature  of  melting 
ice  and  zero  as  the  temperature  of  boiling  water.  The  Centi- 
grade scale  was  evidently  designed  as  part  and  parcel  of  the 
metric  system,  which  originated  in  France  and  was  there 
definitely  adopted  in  1799.  The  Centigrade  scale  is  in  general 
use  among  scientific  men  throughout  the  world. 

36. — Air  Thermometer. — Galileo  Galilei,  commonly  called 
Galileo  (1564-1642),  an  Italian  astronomer  and  physicist,  in- 
vented the  air  thermometer  about  1593  for  the  use  of  physi- 


HEAT  AND  THERMAL  EXPANSION 


75 


cians.    It  consisted  of  a  sizable  blown  glass  bulb  on  the  end  of 
a  tube  of  small  bore,  a  scale  being  attached  to  the  tube.     The 


TEMPERATURE  CONVERSION   TABLE 
Centigrade    to    Fahrenheit    to    Reaumur. 


c. 

F. 

R. 

C. 

F. 

R. 

C. 

F. 

R. 

+100° 

+212. 0<= 

+80.0° 

+53" 

+127.4° 

+42.4" 

+  6° 

+42.8° 

+4.8» 

99 

210.2 

79.2 

52 

125.6 

41.6 

5 

41.0 

4.0 

98 

208.4 

78.4 

51 

123.8 

40.8 

4 

39.2 

3.2 

97 

206.6 

77.6 

50 

122.0 

40.0 

3 

37.4 

2.4 

96 

204.8 

76.8 

49 

120.2 

39.2 

2 

1.6 

95 

203.0 

76.0 

48 

118.4 

38.4 

1 

33.8 

0.8 

94 

201.2 

75.2 

47 

116.6 

37.6 

Zero 

32.0 

Zero 

93 

199.4 

74.4 

46 

114.8 

36.8 

-  1 

30.2 

-  0.8 

S2 

197.6 

73.6 

45 

113.0 

36.0 

2 

28.4 

1.6 

91 

195.8 

72.8 

44 

111.2 

35.2 

3 

26.6 

2.4 

90 

194.0 

72.0 

43 

109.4 

34.4 

4 

24.8 

3.2 

89 

192.2 

71.2 

42 

107.6 

33.6 

5 

23.0 

4.0 

88 

190.4 

70.4 

41 

105.8 

32.8 

6 

21.2 

4.8 

87 

188.6 

69.6 

40 

104.0 

32.0 

7 

19.4 

5.6 

§6 

186.8 

68.8 

39 

102.2 

31.2 

8 

17.6 

6.4 

85 

185.0 

68.0 

38 

100.4 

30.4 

9 

15.8 

7.2 

84 

183.2 

67.2 

37 

98.6 

29.6 

10 

14.0 

8.0 

83 

181.4 

66.4 

36 

96.8 

28.8 

11 

12.2 

8.8 

§2 

179.6 

65.6 

35 

95.0 

28.0 

12 

10.4 

9.6 

81 

177.8 

64.8 

34 

93.2 

27.2 

13 

8.6 

10.4 

80 

176.0 

64.0 

33 

91.4 

26.4 

14 

6.8 

11.2 

79 

174.2 

63.2 

32 

89.6 

25.6 

15 

5.0 

12.0 

78 

172.4 

62.4 

31 

87.8 

24.8 

16 

3.2 

12.8 

V 

170.6 

61.6 

30 

24.0 

17 

1.4 

13.6 

76 

168.8 

60.8 

29 

84:2 

23.2 

18 

-0.4 

14.4 

75 

167.0 

60.0 

28 

82.4 

22.4 

19 

2.2 

15.2 

74 

165.2 

59.2 

27 

80.6 

21.6 

20 

4.0 

16.0 

73 

163.4 

58. 4 

26 

78.8 

20.8 

21 

5.8 

16.8 

72 

161.6 

57.6 

25 

77.0 

20.0 

22 

7.6 

17.6 

71 

159.8 

56.8 

24 

75.2 

19.2 

23 

9.4 

18.4 

70 

158.0 

56.0 

23 

73.4 

18.4 

24 

11.2 

19.2 

69 

156.2 

55.2 

22 

71.6 

17.6 

25 

13.0 

20.0 

68 

154.4 

54.4 

21 

16.8 

26 

14.8 

20.8 

67 

152.6 

53.6 

20 

68^0 

16.0 

27 

16.6 

66 

150.8 

52.8 

19 

66.2 

15.2 

28 

18.4 

22!4 

65 

149.0 

52.0 

18 

64.4 

14.4 

29 

20.2 

23.2 

64 

147.2 

51.2 

17 

62.6 

13.6 

30 

22.0 

24.0 

63 

145.4 

50.4 

16 

60.8 

12.8 

31 

23.8 

24.8 

62 

143.6 

49.6 

15 

59.0 

12.0 

32 

25.6 

25.6 

61 

141.8 

48.8 

14 

57.2 

11.2 

33 

27.4 

26  4 

60 

140.0 

48.0 

13 

55.4 

10.4 

34 

29.2 

27.2 

G9 

138.2 

47.2 

12 

53.6 

9.6 

35 

31.0 

28.0 

58 

136.4 

46.4 

11 

51.8 

8.8 

36 

32.8 

28.8 

57 

134.3 

45.6 

10 

50.0 

8.0 

37 

34.6 

29.6 

56 

132.8 

44.8 

9 

48.2 

7.2 

38 

36.4 

30.4 

55 

131.0 

44.0 

8 

46.4 

6.4 

39 

38  2 

31.2 

54 

129.2 

43.2 

7 

44.6 

5.8 

40 

40.0 

32.0 

Fahrenheit  degrees  =  1.8  X  Centigrade  degrees  +  32°. 
Centigrade  degrees  =  (Fahrenheit  degrees)  —  32°-ri.8. 

bulb  Avas  heated  in  order  to  expand  and  expel  some  of  its  air 
content,  and  then  the  stem  was  inserted  in  a  colored  liquid,  as 
pigmented  water  or  alcohol.    As  the  air  in  the  bulb  and  stem 


76 


CORK  INSULATION 


cooled,  the  air  contracted,  and  atmospheric  pressure  caused 
the  liquid  to  rise  in  the  tube.  Fixed  points  were  then  estab- 
lished on  the  scale,  and  any  rise  in  temperature  caused  the 
colored  liquid  to  drop  and  any  drop  in  temperature  caused 
the   liquid   to  rise.     The   instrument   was   remarkable   for  its 


jelG.   30.— EARLY   FORM   OF  AIR   THERMOMETER. 


sensitiveness,  but  its  readings  changed  for  every  change  in 
barometric  pressure. 

The  modern  "air  thermometer"  is  an  apparatus  for  meas- 
uring the  ratio  of  two  temperatures  by  observation  of  the  pres- 
sures of  a  confined  portion  of  hydrogen  gas  at  the  respec- 
tive temperatures,  based  on  the  necessary  modification  of  the 
Law  of  Charles,  laid  down  in  1787,  which  claimed  to  estab- 


HEAT  AND  THERMAL  EXPANSION  11 

lish  that  "the  volume  of  a  given  mass  of  any  gas  under  con- 
stant pressure  increases  by  a  constant  fraction  of  its  volume 
at  zero  for  each  rise  of  temperature  of  1°C."  The  ratio  of 
standard  steam  temperature  (the  minimum  temperature  of 
pure  steam  at  16  cm.  pressure)  to  ice  temperature  (the  tem- 
perature of  pure  melting  ice  at  76  cm.  pressure)  has  been 
found  by  the  air  thermometer  to  be  1.367,  or 

Steam  temp.      S 
=— =  1 .367 


Ice  temp.         I 

On  the  Centigrade  scale  S  —  I  =  100,  and  from  these 
two  simple  equations  we  find  that  S  =  ZTh°  and  I  =  273°, 
approximately,  Centigrade.  Any  other  temperature  may  be 
determined  by  measuring  its  ratio  to  I  or  to  S  by  means  of 
the  air  thermometer.  Temperatures  measured  in  this  way 
are  called  absolute  temperatures,  and  thus  it  will  be  noted  that 
the  absolute  zero  on  the  Absolute  scale  is  273  degrees  below 
the  freezing  point  on  the  Centigrade  scale.  It  has  been 
established,  since  Jacques  Alexandre  Cesar  Charles  (1746- 
1822),  a  French  physicist  and  aeronaut,  gave  us  his  Law  of 
Charles,  that  the  volumes  of  the  same  mass  of  gas  under 
constant  pressure  are  proportional  to  the  temperature  on 
this  Absolute  scale,  or 

V        t+213         T 

vi        U+213        T, 
if  t  +  273  is  expressed  by  T,  and  t^  -f  273  by  Tj. 

37. — Expansion  and  Contraction. — If  equal  volumes  of 
various  gases  are  heated,  under  constant  pressure,  they  were 
thought  by  Joseph  Louis  Gay-Lussac  (1778-1850),  a  French 
chemist  and  physicist,  to  expand  equivalent  amounts  for  the 
same  rise  in  temperature,  but  very  careful  measurements  have 
since  demonstrated  quite  perceptible  differences  of  expansion 
of  various  gases,  ammonia,  for  example,  being  distinctly  dif- 
ferent in  its  expansion  from  hydrogen.  Gases  that  are  near 
their  points  of  liquefaction  depart  widely  from  Gay-Lussac's 
law ;  ammonia,  sulphur  dioxide  and  methyl  chloride  gases  are 
easily  liquefied  and  are  commonly  referred  to  as  vapors. 
Hydrogen,  on  the  other  hand,  is  not  easily  liquefied  under 


78 


CORK  INSULATION 


ordinary  pressures,  and  hence  follows  Gay-Lussac's  law  quite 
closely.  The  point  of  importance  here  is  that  all  gases  ex- 
pand when  heated  and  contract  when  cooled. 

Liquids,  with  notable  exceptions,  expand  when  heated  and 
contract  when  cooled,  the  amount  in  any  case  depending 
entirely  upon  the  volume  of  the  substance.  An  exception  is 
water,  which  contracts  when  heated  from  0°  C.  (32°  F.)  to 
4°  C.  (39.2°  F.). 

Solids,  with  a  few  exceptions,  expand  in  all  directions  when 
heated  and  contract  when  cooled.  An  exception  is  iodide  of 
silver,  which,  within  a  certain  temperature  range,  contracts 
when  heated  and  expands  when  cooled. 

38. — Force  of  Expansion  and  Contraction. — The  force  of 


/ 

/ 

1.03 

«A 

/ 

-J 

tj 

/ 

^ 
^ 

z 

/ 

/ 

1 

s 

5 

/ 

/ 

cr 

s 

y 

/ 

1 

y 

/ 

^ 

1 

1 

^ 

■^ 

TEM 

'ERA1 

URES 

FIG.    31.— GRAPHIC    REPRESENTATION    OF    THE    EXPANSION    AND    CON- 
TRACTION  OF   WATER    WITH    CHANGE   OF   TEMPERATURE. 

expansion  or  of  contraction  of  a  substance  is  equal  to  the 
force  required  to  compress  or  expand  it  to  the  same  extent  by 
mechanical  means.  This  force  must  be  computed  by  some 
method  suited  to  the  conditions,  such  as  illustrated  in  this 
example*:  A  bar  of  iron,  one  square  inch  in  cross-sectional 
area,  if  placed  under  the  tension  of  a  ton,  increases  in  length 
0.0001  of  itself.     The  coefficient  of  linear  expansion  of  this 

'Physics,"   Allyn    and    Bacon, 


•Henry   S.    Carhart  and   Horatio   N.   Chute,    1901, 
Boston  and  Chicago. 


HEAT  AND  THERMAL  EXPANSION  79 

iron  is  0.0000122.  Since  0.0001  -^  0.0000122  =  8+,  then  a 
change  of  temperature  of  approximately  8°  C.  will  produce 
the  same  change  in  the  length  of  the  bar  as  a  force  of  one  ton. 

39. — Application  of  Expansion  and  Contraction. — Many  of 
the  phenomena  that  are  commonly  encountered  are  traceable 
directly  to  the  expansion  and  contraction  that  results  from 
the  rise  and  fall  of  temperature.  One  of  the  commonest  of 
these  is  the  explanation  for  a  pendulum  clock  losing  time  in 
hot  weather  and  gaining  time  in  cold  weather,  due  to  the 
expansion  and  contraction,  respectively,  of  its  pendulum  with 
the  seasons.  The  wagon-maker  heats  his  iron  tires,  thus 
expanding  them,  and  after  being  put  in  place  they  contract 
and  bind  the  wooden  wheel  solidly  and  securely.  Very  hot 
water  if  poured  into  a  cold  glass  will  often  crack  the  glass 
due  to  unequal  expansion  of  the  inner  and  outer  surfaces. 
The  steel  framework  of  modern  buildings  is  put  together  with 
red-hot  rivets  hammered  down  as  tight  as  possible  with  pneu- 
matic hammers.  When  the  rivets  cool  they  contract  and 
draw  the  steel  members  together  with  an  enormous  force. 
Virtually  all  pipe  lines  must  be  so  arranged  or  equipped  as 
to  allow  for  expansion  and  contraction,  to  avoid  serious  dam- 
age and  trouble  from  leaks.  Paved  streets,  cement  sidewalks, 
viaducts,  bridges  and  all  such  items  of  general  utility  must 
be  provided  with  a  certain  freedom  of  motion  of  their  stand- 
ardized parts  to  prevent  buckling  and  cracking  from  expan- 
sion and  contraction.  The  terrific  force  exerted  by  the  ex- 
pansion of  freezing  water  splits  off  the  solid  rock  from  the 
side  of  the  granite  hills  with  the  ease  of  a  mythological  giant. 
J*avements  come  up,  trees  are  lifted  out  of  the  ground,  build- 
ing foundations  are  damaged,  water  pipes  burst,  mountain 
ranges  slowly  crumble  away,  all  because  the  terrific  force 
exerted  by  the  expansion  of  freezing  water  is  irresistible. 

Other  phenomena  are  traceable  to  expansion  and  con- 
traction due  to  humidity  rather  than  to  temperature. 

40. — Coefficient  of  Expansion. — It  has  been  noted  that, 
with  very  few  exceptions,  substances  expand  in  every  direc- 
tion when  heated.  Expansion  in  length  is  quite  naturally 
termed  linear  expansion,  expansion  in  area  is  known  as  super- 
ficial expansion  and  expansion  in  volume  is  called  cubical  expan- 


80  CORK  INSULATION 

sion.  If  a  substance  is  heated  from  0°  C.  to  1°  C,  the  fraction 
of  its  length  that  the  body  expands  is  its  cofficient  of  linear  expan- 
sion, the  fraction  of  its  area  that  the  body  expands  is  its  coeffi- 
lient  of  superficial  expansion  and  the  fraction  of  its  volume  that 
the  body  expands  is  its'  coefficient  of  cubical  expansion. 

The  expansion  of  most  substances  has  been  found  to  be  nearly 
constant  for  each  degree  of  temperature,  and  it  is  therefore  the 
practice  to  determine  the  mean  coefficient  for  a  change  of  several 
degrees.  If  1^  is  the  length  of  an  iron  bar  at  temperature  t^ 
and  I2  the  length  at  temperature  tg,  then  the  expansion  in 
length  for  1°  C.  is  expressed  by 

l^li     1,-1, 


i 


ts— t,  t 

if  tj — ti  is  expressed  by  t.  Now  the  fraction  of  its  length  that 
a  body  expands  when  heated  from  0°  C.  to  1°  C.  is  taken  as  its 
coefficient  of  linear  expansion,  which  shall  be  designated  as  a. 
Therefore,  the  original  length,  l^,  times  the  coefficient  of  linear 
expansion  of  the  material,  a,  or  1^  a,  must  equal  the  expansion 
in  length  for  1°  C,  or 

I2— li  U—U 

lia= ,  or  a= ,  or  h^hCl+at); 

t  li  t 

and,  similarly,  if  k  is  the  coefficient  of  cubical  expansion,  Vj 
and  V2  the  volumes  at  temperatures  t^  and  tg,  respectively,  then 

V2 — Vi  Va — Vi 

k= = ,  or  V2=Vi   (1+kt). 

Vi  (t:— ti)  Vi  t 

Superficial  and  cubical  expansion  for  solids  are  computed 
from  the  linear  expansion,  the  coefficient  of  superficial  expansion 
being  twice  and  the  coefficient  of  cubical  expansion  being  three 
times  the  coefficient  of  linear  expansion. 

41. — Determination  of  the  Expansion  of  Substances. — The 
linear  or  cubic  expansion  of  a  solid  may  be  determined  by  the 
actual  measurement  of  its  dimensions  at  different  tempera- 
tures, or  its  cubic  expansion  may  be  determined  indirectly  by 
measuring  the  volume  of  the  solid  at  various  temperatures  by 
the  gravimetric  method,  in  common  use  by  chemists. 

The  determination  of  the  expansion  of  water  and  all  other 


I 


HEAT  AND  THERMAL  EXPANSION 


81 


volatile  liquids  is  attended  by  difficulties  due  to  the  formation 
of  vapor  when  heated.  The  most  accurate  results  are  obtained 
by  first  determining  the  volume  of  a  glass  vessel  at  each  of 
various  temperatures  by  weighing  the  vessel  full  of  mercury 
at  those  temperatures  and  then  using  the  vessel  to  determine 
the  density  of  the  given  liquid  at  the  various  temperatures. 
The  accompanying  table  gives  the  results  obtained  in  this  way 
for  water  by  Edward  L.  Nichols  and  William  S.  Franklin 
(The  Elements  of  Physics;  The  MacMillan  Co.,  New  York 
City). 

DENSITIES  AND  SPECIFIC  VOLUMES  OF  WATER. 


Temperature 


Density 


Volume 


—  2° 
0° 

-f  1° 
2" 
3° 
4° 
S" 
6° 
T 
8" 
9' 
lO" 
15° 


35' 
40- 
45* 
50° 
55° 
60° 
6S» 
70° 
75° 
80° 
85° 
90° 
95° 
100° 


0.99815 

0.99869 

0.99912 

0.99945 

0.99970 

0.999874 

0.999930 

0.999970 

0.999993 

1.000000 

0.999992 

0.999970 

0.999932 

0.999881 

0.999815 

0.999736 

0.999143 

0.998252 

0.997098 

0.995705 

0.994098 

0.99233 

0.99035 

0.98813 

0.98579 

0.98331 

0.98067 

0.97790 

0.97495 

0.97191 

0.96876 

0.96550 

0.96212 

0.95863 


1.00186 

1.00131 

1.00088 

1.00055 

1.00031 

1.000127 

1.000070 

1.000030 

1.000007 

1.000000 

1.000008 

1.000030 

1.000068 

1.000119 

1.000185 

1.000265 

1.000858 

1.001751 

1.002911 

1.004314 

1.005936 

1.00773 

1.00974 

1.01201 

1.01442 

1.01697 

1.01971 

1.02260 

1.02569 

1.02890 

1.03224 

1.03574 

1.03938 

1.04315 


The  cubic  expansion  of  various  gases  may  be  obtained  by 
mearis  of  careful  measurements  employing  especially  con- 
structed laboratory  apparatus.  There  are  perceptible  differ- 
ences of  expansion  of  various  gases  at  equal  pressures  for  a 
given  rise  in  temperature;  carbon  dioxide,  ammonia  and  water 
vapor,  for  example,  being  distinctly  different  from  hydrogen, 
nitrogen  and  oxygen,  disproving  the  accuracy  of  Gay-Lussac's 
law. 


CHAPTER  VIII. 

MEASUREMENT  OF  HEAT,  CHANGE  OF  STATE, 
HUMIDITY. 

42. — First  Law  of  Thermodynamics. — When  a  given  sub- 
stance is  heated  by  the  dissipation  of  energy  there  is  a  definite 
relation  between  the  amount  of  work  done  and  the  thermal 
effect  produced,  and  consequently  heat  may  be  measured  in 
units  of  mechanical  work. 

43. — Methods  of  Heat  Measurement. — An  amount  of  heat 
required  to  produce  a  given  thermal  effect  can  be  measured 
by  the  direct  determination  of  the  amount  of  work  required 
to  produce  a  like  eft'ect,  but  this  direct  method  of  heat  meas- 
urement is  not  easy  of  accomplishment  due  in  part  to  the 
difficulty  of  applying  mechanical  work  wholly  to  the  heating 
of  a  given  substance.  The  work  spent  in  a  given  portion  of 
an  electric  circuit,  however,  can  be  measured  with  great  accu- 
racy and  such  work  can  be  readily  employed  to  produce  any 
given  thermal  effect. 

Another  method  of  measuring  heat  employs  the  relation 
between  the  amount  of  work  dissipated  in  heating  water  and 
the  rise  of  temperature  thus  produced.  This  method  is  prac- 
tical, even  though  the  energy-values  are  given  indirectly, 
because  the  procedure  may  be  carried  out  with  accuracy.  The 
melting  of  ice,  and  the  vaporization  of  water,  are  also  fre- 
quently employed  in  the  measurement  of  heat,  since  the  heat 
(work)  necessary  to  melt  a  given  quantity  of  ice  or  to  con- 
vert a  given  quantity  of  water  into  steam  are  known  quantities 
by  determination. 

44. — Units  of  Heat. — The  work  required  to  heat  a  given 
quantity  of  water  has  been  shown  to  be  approximately  pro- 
portional to  the  rise  of  temperature,  and  for  most  purposes 
this  proportion  is  sufficiently  exact.     Consequently,   the  amount 

82 


MEASUREMENT  OF  HEAT  AND  HUMIDITY  83 

of  heat  required  to  raise  the  temperature  of  one  gram  of  water 
one  degree  Centigrade  has  been  adopted  by  physicists  as  a 
practical  unit  of  heat  and  is  known  as  the  calorie.  (The 
standard  caloric  is  the  amount  of  heat  required  to  raise  one 
gram  of  water  from  14.5°  C.  to  15.5°  C.  hydrogen  thermometer, 
and  is  ecjuivalent  to  4.189  joules*.  Engineers  have  fixed  upon 
the  amount  of  heat  required  to  raise  the  temperature  of  one 
pound  of  zvatcr  one  degree  Fahrenheit  as  a  practical  unit  of 
heat,  called  the  British  thermal  unit  (B.t.u.),  and  which  is 
equivalent  to  approximately  778  foot-pounds.) 

45. — Thermal  Capacity  of  a  Substance. — The  number  of 
thermal  units  (units  of  work)  or  the  quantity  of  heat  required 
to  raise  the  temperature  of  a  body  through  one  degree  is  the 
thermal  capacity  of  that  body  at  that  temperature;  thermal 
capacity  varies  slightly  with  temperature,  but  for  many  pur- 
poses is  assumed  to  be  constant.  The  thermal  capacities  of 
equal  masses  of  different  substances  differ  widely,  being  the 
product  of  specific  heat  and  mass. 

46. — Specific  Heat. — Substances  in  general  have  each  a 
definite  specific  heat,  which  may  be  defined  as  the  increase  in 
heat  content  of  a  unit  mass  of  the  substance  per  degree  in- 
crease in  temperature;  or,  the  number  of  thermal  units  (units 
of  work)  necessary  to  raise  the  temperature  of  a  unit  mass 
of  a  substance  through  one  degree,  at  any  temperature,  is 
its  specific  heat  at  that  temperature.  Since  the  Standard  ther- 
mal unit  (calorie)  is  the  amount  of  heat  required  to  raise  the 
temperature  of  one  gram  of  water  from  14.5°  C.  to  15.5°  C, 
then  specific  heat  may  be  expressed  as  the  ratio  of  the  amount 
of  heat  required  to  raise  a  given  weight  of  the  substance  from 

•14.5°  C.  to  15.5°  C,  to  that  required  to  raise  an  equal  weight 
of  water  through  the  same  temperature  range.     By  ignoring 

•the  variation  in  the  specific  heat  of  a  substance  at  different 

temperatures  and  by  taking  one  gram  as  the  unit  of  weight 

and  1°  C.  as  the  rise  of  temperature,  the  definition  becomes: 

Heat  units  required  to  raise  one  gram  of  substance  1°  C. 

Specific  Heat  = 

Heat  units  required  to  raise  one  gram  of  water  1°  C. 

Taking  the  calorie  as  the  heat  unit,  the  denominator  becomes 


•Edward  L.  Nichols  and  Wm.  S.   Franklin,  1904,  "The  Elements  of  Physics,"The 
MacMillan   Co.,  New  York,  N.   Y. 


84  CORK  INSULATION 

equal  to  unity,  by  definition.  Hence  the  specific  heat  of  a 
substance  is  equal  to  the  number  of  calories  required  to  raise 
the  temperature  of  one  gram  1°  C,  and  it  will  be  observed  that 
the  same  figure  is  given  by  the  number  of  B.t.u.  required  to 
raise  one  pound  of  the  substance  1°  F.,  since  by  definition  one 
B.t.u.  will  raise  one  pound  of  water  1°  F. 

The  mean  specific  heat  of  a  substance,  between  any  two 
temperatures,  is  determined  by  dividing  the  heat  given  oflf  per 
unit  mass  in  cooling  from  the  one  temperature  to  the  other, 
by  the  difiference  in  the  temperatures.  The  accompanying 
table  gives  the  specific  heats  of  various  substances  for  the 
mean  temperatures  shown,  and  in  terms  of  water  at  15°  C. 
(5°  F.). 

SPECIFIC  HEATS  OF  VARIOUS  MATERIALS.* 


Substance 

Mean  Temperature 

Specific  Heat 

Water 

5" 

1.0041 

Water 

15° 

1.0000 

Water 

20° 

0.9987 

Ice 

—10" 

0.502 

Paraffin 

10° 

0.694 

Copper 

SO' 

0.092 

Zinc 

so- 

0.093 

Iron 

ls- 

0.109 

Platinum 

SO' 

0.032 

Mercury 

20" 

0.033 

47. — Heat  of  Combustion. — Most  chemical  actions  are  ac- 
companied by  the  generation  or  the  absorption  of  heat;  those 
involving  the  generation  of  heat  are  known  as  exothermic  re- 
actions, and  those  during  the  progress  of  which  heat  is  ab- 
sorbed are  called  end o thermic  reactions.  The  most  important 
case  of  exothermic  reaction  is  combustion,  the  heat  generated 
per  unit  mass  of  a  substance  burned  being  the  heat  of  com- 
bustion of  that  substance.  The  accompanying  table  gives  the 
heat  of  combustion  of  a  few  substances  in  B.t.u.  per  pound  of 
substance. 

HEAT    OF    COMBUSTION    OF    VARIOUS    MATERIALS.f 

Product  of  Heat  of  Combustion 

Substance                                          Combustion  B.t.u.  per  pound 

Carbon                                                  COo  14,600 

Carbon                                                     CO  4,450 

Carbon   Monoxide                             CO2  10,150 

Hydrogen                                            H2O  62,000 
Methane                                             (CO2) 

(H2O)  23,550 

Sulphur                                               SO2  <,050 

48. — Changes  of  State  with  Rise  of  Temperature. — When 
a  body  changes  from  the  solid  to  the  liquid  state  by  the  appli- 


*Carhart  &  Chute,   1904,  "Physics,"  Allyn  and   Bacon,   Boston  and  Chicago. 
tThos.  A.   Marsh,   M.E.,   1924. 


MEASUREMENT  OF  HEAT  AND  HUMIDITY  85 

cation  of  heat,  it  is  said  to  melt,  or  fuse,  or  liquefy,  and  the 
temperature  at  which  fusion  or  liquefaction  occurs  is  the 
melting  point.  The  temperature  of  the  substance  then  remains 
constant  until  the  complete  change  to  the  liquid  state  has  been 
accomplished,  when,  under  continued  application  of  heat,  the 
temperature  rises  again  until  the  liquid  begins  to  boil  or 
vaporize,  and  the  temperature  at  which  vaporisation  occurs 
is  the  boiling  point.  The  temperature  again  remains  constant 
until  the  liquid  is  entirely  changed  to  vapor,  when  the  tem- 
perature once  more  begins  to  rise. 

49. — The  Melting  Point. — The  temperature  at  which  the 
solid  and  liquid  forms  of  a  substance  are  capable  of  existing 
together  in  equilibrium,  is  the  melting  point  of  that  substance, 
and  such  temperature  is  invariable  for  every  crystalline  sub- 
stance if  the  pressure  is  constant.  Some  substances,  like  wax, 
resin,  glass  and  wrought  iron,  have  no  sharply  defined  melting 
points.  They  first  soften  and  then  pass  more  or  less  slowly 
into  the  condition  of  a  viscous  liquid,  which  property  per- 
mits of  the  bending  and  forming  of  glass  and  the  welding 
and  forging  of  iron. 

Most  substances  expand  on  melting,  or  occupy  a  larger 
volume  in  the  liquid  state  than  in  the  solid.  A  notable  and 
important  exception  is  water,  which  upon  freezing,  or  solidi- 
fying, increases  its  volume  nine  per  cent.  Tf  this  expansion 
is  resisted,  water  in  freezing  is  capable  of  exerting  an  enor- 
mous force. 

The  accompanying  table  gives  the  melting  points  of  some 
solids  at  atmospheric  pressure. 

MELTING  POINTS  OF  VARIOUS  SOLIDS. 
Substance  Temperature,   F. 

Nickel     2732° 

Gold    1947  : 

Aluminum     1Z14 

Zinc     786° 

Lead    620° 

Tin     449° 

Mercury      — ^^ 

50.— Heat  of  Fusion.— When  a  solid  begins  to  melt,  or  fuse, 
by  the  application  of  heat,  the  heat-energy  imparted  to  the 
substance  is  fully  employed  in  producing  change  of  state,  its 
temperature    remaining   constant   until    fusion    is    completed. 


86  CORK  INSULATION 

The  heat  of  fusion  of  a  substance  is  the  number  of  thermal 
units  required  to  change  a  unit  mass  of  a  solid  at  its  melting 
point  into  liquid  at  the  same  temperature.  The  accompany- 
ing table  gives  the  heat  of  fusion  of  various  substances. 

HEAT    OF    FUSION    OF   VARIOUS    SUBSTANCES.* 

Substance  B.t.u.  per  Pound 

Bismuth     22.7 

Lead     9.7 

Mercury     5.04 

Nickel    8.3 

Platinum    49.0 

Silver   38.0 

Tin    25.7 

Zinc    50.6 

Ice    144.0 

Hydrogen    28.8 

51. — The  Boiling  Point. — The  temperature  at  which  the 
liquid  and  its  pure  vapor  can  exist  together  in  equilibrium,  is 
the  boiling  point  of  that  liquid,  and  such  temperature  is  invari- 
able if  the  pressure  is  constant. 

The  vapor  of  a  substance  under  given  pressure  will  con- 
dense to  a  liquid  if  it  is  cooled  below  the  temperature  that  is 
its  boiling  point  at  that  pressure;  and  the  vapor  of  a  substance 
at  given  temperature  will  condense  to  a  liquid  if  its  pressure 
is  increased  beyond  a  certain  maximum  value  for  that  sub 
stance,  although  all  vapors  have  a  critical  temperature  above 
which  they  can  not  be  liquified  regardless  of  the  amount  of 
pressure  to  which  they  are  subjected. 

The  accompanying  table  gives  the  boiling  points  of  various 
liquids  at  atmospheric  pressure. 

BOILING   POINTS    OF  VARIOUS    LIQUIDS.* 

Substance  Boiling  Point,  F. 

Ether      95° 

Chloroform     142° 

Alcohol    172.2° 

Benzine     176.7° 

Water    212° 

Glycerine     554° 

Mercury 675  ° 

Sulphur  dioxide 14° 

Ammonia    —  29° 

Carbon   dio.xide    — 108.5° 

Oxygen   — 296° 

Hydrogen    — 422° 

52. — Vaporization. — The  conversion  of  a  substance  into 
the  gaseous  form  is  called  vaporizatioin.  If  the  change  to  a  gas 
takes  place  slowly  and  from  the  surface  of  a  liquid,  at  a  tem- 

•Chas.   R.  Darling,   1908. 


MEASUREMENT  OF  HEAT  AND  HUMIDITY  87 

perature  below  the  normal  boiling  point,  it  is  called  evapora- 
tion; but  if  rapid  internal  evaporation  visibly  agitates  a  liquid, 
and  the  bubbles  that  rise  through  the  liquid  are  pure  vapor, 
the  process  is  called  boiling.  If  a  small  quantity  of  liquid  is 
placed  on  hot  metal,  it  assumes  a  globular  form  and  vaporizes 
at  a  rate  somev^^here  between  ordinary  evaporation  and  boiling. 
The  vapor  acts  as  a  cushion  and  prevents  actual  contact  be- 
tween the  liquid  and  the  metal,  while  the  globular  form  is 
due  to  surface  tension.  This  variety  of  vaporization  is  called 
the  spheroidal  state,  and  the  phenomenon  is  sometimes  also 
referred  to  as  the  caloric  paradox. 

When  a  substance  passes  directly  from  the  solid  to  the 
gaseous  state,  without  passing  through  the  intermediate  state 
of  a  liquid,  it  is  said  to  sublime.  Some  substances,  such  as 
iodine  and  camphor,  sublime  at  atmospheric  pressure  but 
melt  if  the  pressure  be  sufficiently  increased.  If  ice  is  held  at 
a  temperature  below  freezing,  it  sublimes  (evaporates) 
slowly,  which  fact  is  of  some  importance  in  the  storing  of  ice. 

53. — Heat  of  Vaporization. — When  a  liquid  begins  to  boil, 
or  vaporize,  by  the  application  of  heat,  the  heat-energy  im- 
parted to  the  substance  is  fully  employed  in  producing  change 
of  state,  its  temperature  remaining  constant  until  vaporization 
is  complete.  The  heat  of  vaporization  of  a  liquid  is  the  num- 
ber of  thermal  units  required  to  change  a  unit  mass  of  the 
liquid  at  its  boiling  point  into  vapor  at  the  same  temperature. 
The  accompanying  table  gives  the  heat  of  vaporization  of 
various  substances  at  atmospheric  pressure. 

HEAT    OF   VAPORIZATION    OF    VARIOUS    SUBSTANCES.* 

Substance  B.t.u.  per  Pound 

Water    967 

Ether     164 

Mercury    112 

Turpentine     133 

Air     99 

Carbon    dioxide     °o 

Ammonia    531 

Oxygen     ., 101 

Hydrogen     ' 360 

54. — Superheating  and  Undercooling  of  Liquids. — When 
pure  water  that  is  free  from  air  is  heated  in  a  clean  vessel,  its 
temperature  usually  rises  as  much  as  from  eight  to  twelve 
degrees  above  its  normal   boiling  point  before   it  begins  to 

"Chas.  R.  Darling,  1908. 


88  CORK  INSULATION 

vaporize,  and  when  vaporization  begins  it  occurs  violently 
and  is  attended  by  an  immediate  fall  of  temperature  to  the 
normal  boiling  point.  If  pure  water  is  cooled,  its  temperature 
usually  falls  a  number  of  degrees  below  its  normal  freezing 
point  before  freezing  actually  begins,  but  a  large  amount  of 
ice  is  then  suddenly  formed  and  the  temperature  quickly  rises 
to  the  normal  freezing  point.  These  phenomena  are  common 
to  most  liquids,  but  the  converse  is  not  true ;  that  is,  water 
vapor  will  not  condense  until  it  reaches  its  normal  condensing 
point,  and  ice  begins  to  melt  immediately  upon  reaching  its 
normal  melting  point. 

55. — Critical  Temperatures. — When  a  liquid  and  its  vapor 
are  confined  in  a  vessel  and  heated,  a  portion  of  the  liquid 
vaporizes,  the  pressure  increases,  the  density  of  the  vapor 
increases  and  possibly  the  density  of  the  liquid  decreases. 
When  that  temperature  is  reached  where  the  density  of  the 
liquid  and  of  the  vapor  become  identical,  the  liquid  and  the 
vapor  are  physically  identical  and  this  temperature  is  called 
the  critical  temperature  of  the  liquid.  Thus  the  heat  of  va- 
porization of  a  liquid  is  zero  at  its  critical  temperature.  In 
the  following  table  the  critical  temperatures  of  various  sub- 
stances are  given : 

CRITICAL    TEMPERATURES    OF    VARIOUS    REFRIGERANTS*. 

Substance                               Chemical  Symbol  Degrees  F. 

Sulphur    dioxide     SO2  311.0 

Ammonia     NH3  271.4 

Methyl    chloride    CH3CI  289.0 

Carbon   dioxide    CO2  88.2 

Ethyl  chloride    C0H5CI  360.5 

Butane   C4H10  311.0 

Nitrous  oxide   N2O  95.7 

Propane    CsHg  216.0 

Ethane    C-Ue  90.0 

Methane     CH^  '                                   —115.6 

Ether    CiHioO  

56. — Saturated  Vapor. — A  vapor  is  said  to  be  saturated 
when  it  is  at  its  maximum  pressure  for  a  given  temperature, 
or  when  it  is  at  its  minimum  temperature  for  a  given  pressure. 

57. — Effect  of  Pressure  on  Melting  Point. — Change  of  pres- 
sure varies  but  slightly  the  melting  points  of  substances,  but 
the  lowering  of  the  melting  point  of  ice  by  increase  of  pressure 

'Compiled   from   data   by   H.    D.    Edwards   and    U.    S.    Bureau   of   Standards. 


MEASUREMENT  OF  HEAT  AND  HUMIDITY  89 

is  responsible  for  several  common  phenomena.  The  melting 
of  ice  at  a  point  where  it  is  subjected  to  pressure  and  the 
immediate  freezing  of  the  resulting  water  when  it  flows  out 
of  the  region  of  pressure  is  known  as  rcgelation.  The  excep- 
tional ease  with  which  a  skater  glides  over  the  ice  when  the 
temperature  of  the  atmosphere  is  not  too  low  is  due  largely  to 
the  formation  of  a  thin  layer  of  water  in  the  region  of  extra 
pressure  under  the  skate  runners,  which  water  freezes  almost 
instantly  when  the  skate  has  passed  and  the  pressure  is  relieved. 
Similarly,  the  ready  packing  of  snow  into  balls  is  made  pos- 
sible by  the  melting  of  the  snow  crystals  at  their  points  of 
contact  under  the  extra  pressure  of  the  hands  and  the  imme- 
diate freezing  of  the  resulting  water  as  it  flows  out  of  the 
small  regions  of  pressure,  although  snow  must  be  near  the 


FIG.    32.— MELTAGE   OF   LOWER   TIERS   OF   ICE   IN   LARGE  ICE   STORAGES 

DUE  TO  PRESSURE  IS  AN  IMPORTANT  CONSIDERATION  IN  THE 

DESIGN    OF    SUCH    STRUCTURES. 

melting  point  in  order  that  regelation  may  be  caused  by  the 
slight  pressure  produced  by  the  hands.  John  Tyndall  (1820- 
1893),  a  British  physicist,  regarded  the  apparent  plasticity  of 
glacier-ice  as  due  to  continued  minute  fracture  and  regelation. 
The  phenomenon  of  regelation  is  of  practical  importance  to 
the  manufacturer  of  ice  because  of  the  meltage  of  the  lower 
layers  of  ice  cakes  due  to  the  pressure  of  the  layers  stored 
above. 

58. — Effect  of  Pressure  on  Boiling  Point.— Change  of  pres- 
sure varies  greatly  the  boiling  point  of  a  liquid.  At  a  pressure 
of  9.198  cm.  of  mercury  the  boiling  point  of  water  is  but  50° 
C,  at  a  pressure  of  76  cm.  its  boiling  point  is  100°  C,  and  at 


90  CORK  INSULATION 

a  pressure  of  358.1  cm.  its  boiling  point  is  150°  C.  At  a 
pressure  of  86.64  cm.  the  boiling  point  of  liquid  ammonia  is 
—30°  C,  and  at  a  pressure  of  1,945.6  cm.  its  boiling  point  is 
60°  C.  The  variation  of  boiling  point  with  change  of  pressure 
is  of  utmost  importance  in  connection  with  mechanical  refrig- 
eration, as  is  shown  in  any  text  pertaining  to  the  ammonia 
refrigerating  machine. 

59. — Boiling  and  Melting  Points  of  Mixtures. — When  pure 
water  has  a  foreign  substance  dissolved  in  it,  such  as  finely 
divided  ammonium  nitrate,  for  example,  a  thermometer  will 
show  a  sensible  fall  of  temperature,  known  as  heat  lost  in  solu- 
tion, while  its  freezing  point  is  lowered  and  its  boiling  point 
is  raised.  Similarly,  ice  in  a  strong  solution  of  common  salt 
(NaCl)  has  a  very  low  melting  point,  about  5°  F.  (  —  15"  C),  and 
remains  at  that  temperature  until  all  the  ice  is  melted  by  heat 
absorbed  from  surrounding  objects ;  thus  a  vessel  of  water,  or 
a  can  of  ice  cream  mix,  surrounded  by  cracked  ice  and  salt, 
gives  up  its  heat  to  the  low  temperature  mixture  until  the 
water  or  cream  is  frozen. 

It  is  commonly  supposed  that  salt  sprinkled  on  icy  side- 
walks melts  the  ice ;  but  the  fact  is  that  the  salt  lowers  the 
melting  point  of  the  ice  below  surrounding  temperatures  (if 
they  are  not  below  about  5°  F.)  and  these  surrounding  sub- 
stances then  give  up  heat  to  the  ice,  which  melts  it. 

The  use  of  ice  and  salt  as  a  freezing  mixture  is  so  common 
as  to  require  no  further  treatment  here.  However,  it  is  be- 
lieved that  it  offers  such  possibilities  in  the  industries  as  to 
justify  serious  study  and  application. 

60, — Cold  by  Evaporation. — If  a  few  dro]is  of  ether  are 
placed  on  the  bulb  of  a  thermometer,  the  mercury  column  will 
drop  due  to  the  fact  that  some  of  the  heat  of  the  mercury  will 
be  used  to  do  work  on  the  ether  in  evaporating  it.  Sprink- 
ling the  lawn,  shrubbery  and  trees  cools  the  surrounding  air, 
because  of  the  heat  expended  in  evaporating  the  water.  A 
liquid  is  cooled  in  a  porous  vessel  by  the  evaporation  from 
the  outside  surface  of  that  part  of  the  liquid  that  seeps  through 
the  vessel.     Liquid   carbon   dioxide    (CO,)    evaporates   so   rap- 


MEASUREMENT  OF  HEAT  AND  HUMIDITY  91 

idly  as  to  readily  freeze  itself*.  The  rapid  evaporation  of 
liquid  ammonia  is  one  of  the  properties  that  makes  this  chemi- 
cal of  so  much  value  as  a  refrigerating  medium. 

61. — Condensation  and  Distillation. — All  the  heat  that  dis- 
appears during  the  vaporization  of  a  liquid  is  generated  again 
when  the  vapor  is  condensed  back  to  its  original  liquid  form, 
which  principle  is  employed  to  advantage  in  steam  heating. 
Some  gases  will  assume  a  liquid  form  through  their  affinity 
for  a  liquid,  as  exemplified  by  the  affinity  of  ammonia  gas  for 
-water,  the  gas  being  rapidly  absorbed  by  the  water  with  a 
marked  rise  of  temperature. 

Pure  water,  free  from  foreign  substances  such  as  vegetable 
and  mineral  matter,  is  obtained  by  distillation,  which  involves 
both  vaporization  and  condensation.  Alcohol  may  be  sep- 
arated from  fermented  liquors,  for  example,  through  distilla- 
tion, because  if  two  or  more  liquids  are  mixed  together  the 
more  volatile  will  be  vaporized  by  heat  first  and  can  be 
condensed  and  collected  by  itself. 

62. — The  Dew  Point. — The  dew  point  of  the  atmosphere 
at  given  pressure  is  the  temperature  at  which  the  water  vapor 
of  that  atmosphere  becomes  saturated  and  begins  to  condense. 
For  examplef,  air  at  64°  F.  temperature,  30  inches  barometric 
pressure  and  containing  6.24  grains  of  moisture  per  cubic  foot, 
when  cooled  to  62°  F.  will  have  reached  its  dew  point,  while 
air  at  the  same  temperature  and  pressure  but  containing  5.19 
grains  of  moisture  per  cubic  foot  must  be  cooled  to  57°  F. 
before  its  dew  point  is  reached. 

The  amount  of  moisture  that  a  given  volume  of  air  can 
retain  at  given  pressure  depends  on  the  temperature  of  the  air. 
For  example,  a  cubic  foot  of  air  at  64°  F.  temperature  and  30 
inches  barometric  pressure  can  contain  6.55  grains  of  moisture 
before  precipitation  takes  place,  while  a  cubic  foot  of  air  at  60° 
F.  temperature  and  30  inches  barometric  pressure  requires  but 
5.75  grains  of  moisture  to  saturate  it. 

63. — Humidity. — The  amount  of  water  in  the  air  at  any 
given  temperature  and  pressure  is  called  the  absolute  humidity 


*See    "Solid    Carbon    Dioxide — A    New    Commercial    Refrigerant,"    by   the   Dry   Ice 
Corporation   of   America.    50    East   4_'d    St.,   New   York    City. 
tCarrier  Air  Conditioning  Co.,  Newark,  N.  J. 


92  CORK  INSULATION 

of  such  air  at  that  temperature  and  pressure.  However,  such 
absolute  humidity  cannot  exceed  a  certain  fixed  value,  known 
as  absolute  humidity  at  saturation,  for  any  given  temperature 
and  pressure  and  cannot,  of  course,  be  less  than  zero.  For 
example*,  air  at  64°  F.  temperature  and  30  inches  barometric 
pressure  cannot  have  an  absolute  humidity  of  more  than  6.56 
grains  of  moisture  per  cubic  foot,  nor  less  than  zero,  which  is 
perfectly  dry  air  containing  no  moisture. 

The  amount  of  moisture  in  the  air  expressed  in  hundredths 
of  what  that  air  would  contain  were  it  saturated  at  the  given 
temperature  and  pressure,  is  called  relative  humidity.  For 
example*,  air  at  64°  F.  temperature,  30  inches  barometric 
pressure  and  having  an  absolute  humidity  of  6.24  grains  of 
moisture  per  cubic  foot,  has  a  relative  humidity  of  95  (95/lOOth 


FIG.  33.— SLING  PSYCHROMETER. 

of  6.56  grains,  the  maximum  amount  of  moisture  such  air 
would  contain  if  completely  saturated).  When  the  relative 
humidity  is  low,  the  air  is  said  to  be  dry;  and  when  the 
relative  humidity  is  high,  the  air  is  said  to  be  moist. 

The  relative  humidity  and  the  dew  point  of  air  are  usually 
determined  by  the  use  of  an  instrument  called  a  psychrometer. 
The  sling  psychrometer  consists  of  a  wet  bulb  and  a  dry  bulb 
thermometer  suitably  mounted  and  attached  to  a  handle  so 
that  they  may  be  rotated.  A  wet  bulb  thermometer  is  one 
having  a  piece  of  soft  cloth  or  wick,  which  is  kept  moist  with 
water,  covering  its  bulb ;  while  a  dry  bulb  thermometer  has  its 
bulb  exposed  to  the  air.  When  the  sling  psychrometer  is 
rotated  or  whirled  at  from  150  to  200  revolutions  per  minute 
(r.p.m.),  evaporation  takes  place  on  the  wet  bulb  thermome- 
ter and  a  depressed  temperature  reading  is  secured,  and  by 
means  of  the  temperature  readi 
thermometers  it  is  possible  to  determine 


re  readmg  is  secured,  and  by  _ 
lings  on  the  wet  and  dry  bulb  ■ 
termine  the  relative  humidity;t  « 


*Carrier   Air    Conditioning    Co.,    Newark,    N.    J. 

tSee  Appendix   for  "Relative   Humidity  Table,   Percent." 


MEASUREMENT  OF  HEAT  AND  HUMIDITY 


93 


the  dew  point  and  the  amount  of  water  vapor  in  the  air 
(absolute  humidity)  from  psychrometric  tables  published  by 
the  United  States  Department  of  Agriculture,  Weather  Bureau 
Bulletin  No.  235*. 

Air  that  is  saturated  has  a  dew  point  and  dry  bulb  and 
wet  bulb  temperatures  that  are  identical ;  and  if  such  air  is 
cooled,  the  volume  will  be  contracted  and  some  of  the  moist- 
ure will  be  condensed.  If  air  is  but  partly  saturated,  and  the 
temperature  is  reduced,  by  removal  of  heat  from  such  air,  the 
dry  bulb  temperature  falls  and  the  wet  bulb  temperature  falls 
until  they  finally  reach  the  dew  point  temperature,  at  which 
point  the  air  is  completely  saturated, 

RELATIVE    HUMIDITIES   IN   VARIOUS    CITIES. 
(U.    S.    Weather    Reports.) 

Average    Annual    Humidities    for    Various    Cities    of    United    States. 
City  8  a.  m.  8  p.  m. 


Albany,  N.  Y. 
Asheville,  N.  C. 
Atlanta,   Ga. 
Atlantic   City,  N.  J. 
Augusta,  Ga. 
Baltimore,  Md. 
Boston,    Mass. 
Hartford.    Conn. 
Jacksonville,  Fla. 
Key  West,  Fla. 
Macon,   Ga. 
New   Haven,    Conn. 
New  York,  N.  Y. 
Norfolk,  Va. 
Philadelphia,    Pa. 
Portland,    Me. 
Providence,  R.   I. 
Savannah,   Ga. 
Washington,   D.   C. 
Wilmington,   N.    C. 
Birmingham,  Ala. 
Galveston,  Texas 
Mobile,  Ala. 
Montgomery,   Ala. 
New  Orleans,  La. 
Pensacola,    Fla. 
San   Antonio,    Texas 
Tampa,   Fla 
Buffalo,  N.  Y. 
Chattanooga,  Tenn. 
Chicago,   111. 


78 
85 
79 
80 
82 

n 

74 
83 
78 
83 
75 
75 
80 
74 
75 
74 
81 
76 
81 
79 
84 
84 
82 
83 
80 
81 
84 

n 

80 
78 


72 
71 
65 
79 
66 
66 
70 
68 

n 

77 

72 
62 

75 
66 
7i 
71 
75 
68 
77 
65 
78 
74 
64 
72 
75 
53 
76 
73 
63 
71 


•Address,   "Superintendent   of  Documents,   Government   Printing   OfKce,   Washmg- 
ton,  D.   C."     Price.   10  cents. 


94  CORK  INSULATION 

RELATIVE    HUMIDITIES    IN    VARIOUS     CITIES.— Continued. 

(U.    S.    Weather    Reports.) 

Average  Annual   Humidities   for   Various   Cities   of  United   States. 

City  8  a.  m.  8  p.  m. 

__ 

70 
66 
71 
71 
70 
64 
61 
67 
72 
62 
66 
71 

69 
65 
63 
62 
65 
63 
63 
65 

59 
59 
60 
61 
57 
41 
26 
50 
28 
37 
39 
45 
40 
50 
62 
63 
52 
70 
72 
67 


Cincinnati,   Ohio 

76 

Cleveland,  Ohio 

77 

Columbus,  Ohio 

79 

Detroit,  Mich. 

80 

Duiuth,  Minn. 

81 

Grand  Rapids,  Mich. 

82 

Indianapolis,  Inc. 

77 

Louisville,  Ky. 

76 

Dayton,  Ohio 

80 

Milwaukee,  Wis. 

78 

Nashville,  Tenn. 

80 

Pittsburgh,   Pa. 

77 

Rochester,  N.  Y. 

75 

Syracuse,   N.   Y. 

77 

Toledo,  Ohio 

79 

Davenport,  Iowa 

80 

Des  Moines,  Iowa 

80 

Kansas  City,  Mo. 

77 

Memphis,  Tenn. 

79 

St.  Louis,  Mo. 

77 

St.  Paul,  Minn. 

80 

Springfield,   111. 

79 

Fort  Worth,  Texas 

78 

Lincoln,  Neb. 

79 

Oklahoma  City,  Okla. 

80 

Omaha,  Neb. 

78 

Sioux  City,  Iowa 

81 

Wichita,  Kan. 

78 

Denver,  Colo. 

63 

El  Paso,  Texas 

54 

Helena,  Mont. 

68 

Phoenix,  Ariz. 

54 

Pueblo,  Colo. 

64 

Reno,  Nev. 

72 

Salt  Lake  City,  Utah 

60 

Santa  Fe,  N.   Mex. 

58 

Spokane,  Wash. 

77 

Los  Angeles,  Cal. 

78 

Portland,   Ore. 

86 

Sacramento,  Cal. 

82 

San  Diego,  Cal. 

79 

San  Francisco,  Cal. 

87 

Seattle,  Wash. 

87 

CHAPTER  IX. 

TRANSFER  OF  HEAT. 

64. — Heat  Transference. — Heat  is  transmitted  from  a  region 
of  higher  temperature  to  a  region  of  lower  temperature  by  its 
natural  and  continual  tendency  toward  temperature  equilib- 
rium. When  such  temperature  equilibrium  does  not  exist, 
that  is,  when  there  is  a  temperature  difference,  the  natural 
direction  of  the  flow  of  heat  is  toward  the  lower  temperature 
level. 

There  are  three  quite  distinct  processes  by  means  of  which 
heat  is  transferred  from  one  place  to  another,  viz : 

1.  Conduction,  in  which  heat  is  conveyed  by  matter  without  any 
visible  motion  of  the  matter  itself.  This  method  of  transfer  is  assumed 
to  be  accomphshed  by  invisible  molecular  motion  or  communication. 

2.  Convection,  in  which  heat  is  transferred  by  the  visible  motion 
of  heated  matter,  as  by  a  current  of  warm  air  or  the  flow  of  hot 
water  through  a  pipe  circuit.  This  method  of  transfer  is  generally 
accomplished  through  the  fact  of  the  unequal  weights  of  any  given 
matter  at  different  temperatures. 

3.  Radiation,  in  which  heat  is  disseminated  by  a  wave  motion 
in  the  ether,  as  light  is  propogated,  without  the  aid  of  matter.  It  is 
by  this  method  that  heat  and  light  reach  the  earth  from  the  sun. 

The  rate  of  heat  transfer  from  one  region  to  another  obvi- 
ously depends,  therefore,  upon  the  area  of  the  transmitting 
surface,  the  difference  in  temperature  levels,  and  a  unit  heat 
transfer  coefficient  that  combines  the  heat  that  may  be  trans- 
mitted by  conduction,  convection  and  radiation.  The  actual 
magnitude  of  this  composite  heat  transfer  coefficient  is  deter- 
mined in  practice  by  calculation  based  on  theoretical  analysis 
and  experimentation.  The  actual  amount  of  heat  transmitted 
in  any  case, — being  the  product  of  this  coefficient,  the  area, 

95 


96 


CORK  INSULATION 


and  the  temperature  difference, — may  be  expressed  in  symbols, 
thus: 

H=K  A  (ti— t.) 

in  which  H  is  the  total  heat  transfer  in  B.t.u.  per  hour,  K  is 
the  total  heat  transfer  coefficient  in  B.t.u.  per  hour  per  degree 
temperature  difference  F.,  A  is  the  area  of  the  heat  trans- 
mitting surface  in  square  feet,  and  (t^—U)  is  the  temperature 
difference  in  degrees  Fahrenheit  between  the  regions  of  high- 
est and  lowest  levels. 

It  is  evident,  therefore,  that  if  the  heat  transmitting  area 
and  the  temperature  levels  are  held  constant,  the  heat  transfer 
depends  entirely  upon  conduction,  convection  and  radiation. ; 


FIG    34.— TRANSFER    OF    HEAT    BY    CONDUCTION. 

65. — Conduction. — Heat  transfer  by  conduction  is  accom- 
plished in  a  body  of  material  by  the  vibration  or  impact  of 
the  molecules  or  particles  of  matter  that  compose  the  body 
itself,  such  molecular  disturbance  being  produced  by  an  unbal- 
anced thermal  condition  within  the  mass.  Thus  heat  may  be 
interchanged  between  different  parts  of  the  same  body,  or 
between  two  separate  bodies  in  actual  contact,  by  conduction ; 
but  due  to  friction  and  adhesion  between  the  molecules  of  a 
body,  the  vibration  or  impact  of  the  particles  of  matter  will 
become  slower  as  the  heat  energy  passes  from  one  molecule  to 
the  other,  and  consequently  the  amount  of  heat  that  will  be 
transmitted  through  the  body  will  be  something  less  than 
that  applied  to  it.  The  amount  of  heat  that  will  be  trans- 
mitted through  a  given  material,  due  to  a  given  temperature 
difference,  depends  on  the  characteristic  internal  thermal  con- 


J 


TRANSFER  OF  HEAT  97 

ductivity  of  the  material,  each  material  having  its  own  charac- 
teristic rate  of  conduction.  The  metals  are  the  best  conduc- 
tors of  heac.  Wood,  paper,  cloth  and  organic  substances  as 
a  class  are  poor  conductors,  as  are  pulverized  or  powdered 
materials,  partly  because  of  lack  of  continuity  in  the  material. 

The  rate  of  heat  transfer  through  a  homogeneous  material 
having  parallel  sides,  depends  on  the  temperature  difference, 
the  kind  and  condition  of  the  material,  the  thickness  of  the 
material,  and  its  absolute  temperature.    The  heat  transmitted 
by  conduction  may,  in  general,  be  expressed  in  symbols,  thus : 
C 
Hi=— A   (U—U) 
X 
in  which  Hj  is  the  total  heat  transmitted  by  conduction  in 
B.t.u.  per  hour,   C  is  the  coefficient  of  specific  internal  con- 
ductivity in  B.t.u.  per  hour  per  degree  difference  in  tempera- 
ture Fahrenheit  per  inch  of  thickness  of  the  material,  X  is^the 
thickness  of  the  material  in  inches,  A  is  the  area  Oi  the  trans- 
mitting surface  in  square  feet,  and   (tj— tg)   is  the  difference 
beween  the  high  and  the  lov/  surface  temperatures. 

Only  homogeneous  materials'  can  have  a  specific  internal 
conductivity;  and  while  such  conductivity  is  known  to  in- 
crease slowly  with  rise  of  temperature,  it  usually  may  be 
considered  as  constant  for  such  temperatures  as  are  encoun- 
tered in  cold  storage  work.  Resistance  to  heat  flow  is  the 
reciprocal  of  conduction;  and  for  a  given  section  of  a  com- 
pound wall  the  resistances,  not  the  conductions,  are  additive,  j 

Radial  conduction  in  cylindrical  layers  of  materials  is 
not  as  easily  handled  as  conduction  through  layers  of  materials 
having  parallel  sides.  Using  the  insulated  steam  pipe  as  an 
example,  the  flow  of  heat  will  be  relatively  more  rapid  through 
the  material  near  the  pipe  than  farther  out,  since  the  area  for 
the  heat  to  pass  through  is  increasing  toward  the  outside. 
Thus  resistances  are  not  directly  additive  when  considering 
radial  conduction  in  cylinders,  but  the  problem  is  capable  of 
mathematical  solution. 

The  rate  at  which  the  temperature  of  a  material  rises 
should  never  be  taken  as  an  indication  of  its  internal  conduc- 
tivity; because  if  equal  bars  of  iron  and  lead,  for  example, 
are  placed  so  that  one  end  of  each  is  heated  alike,  the  tern- 


98  CORK  INSULATION 

perature  of  the  other  end  of  the  lead  bar  will  risd  first  to  the 
point  of  igniting  a  match,  even  though  iron  is  a  better  con- 
ductor of  heat,  which  is  accounted  for  by  the  fact  that  iron 
has  approximately  four  times  the  specific  heat  of  leavH  and 
thus  requires  about  four  times  as  much  heat  to  produce  .<-he 
same  change  of  temperature.  This  leads  to  the  consideratio^n 
of  conduction  with  changing  temperature.  So  long  as  the  tem,- 
perature  of  parts  of  the  conducting  or  insulating  material  is 
changing,  such  as  when  a  heating  or  cooling  process  is  begiri- 
ning  and  a  steady  state  has  not  been  reached,  the  amounts  .of 
heat  entering  and  leaving  the  material  are  not  the  same.  The 
thermal  capacity,  or  specific  heat,  of  the  material  determines 
the  time  required  to  reach  a  steady  state. 

The  thermometric  conductivity  of  a  material  is  th^  change 
in  temperature  that  is  produced  in  a  unit  vclurne  of  \|:he  mate- 
rial by  the  heat  condueted  through  a  unit  area  in  a  unit  of 
time  with  a  unit  temperature  gradient.  This  value,  which  is 
entirely  different  from  thermal  conductivity,  is  of  importance 
where  protection  against  the  effects  of  fire  is  the  consideration. 

The  internal  thermal  conductivities  of  various  materials, 
as  determined  under  laboratory  test  conditions,  from  experi- 
ments by  the  United  States  Bureau  of  Standards  and  others, 
are  shown  in  the  accompanying  table.  ( Additional'i  tables 
containing  full  data  will  be  found  in  the  Article  on  "Tests  by 
Various  Authorities  on  Many  Materials.") 

To  determine  the  heat  transmitted  by  conduction  through 
a  4-inch  sheet  of  corkboard,  having  surface  temperatures  of 
80°  and  20°  F.,  where  t^  is  80,  t^  is  20,  X  is  4  and  C  (from 
the  accompanying  table)  is  0.308,  apply  such  values  to  the 
formula,  thus : 

0.308 

Hi= (80— 20)  =4.62    B.t.u.     per    hour. 

4 

All  liquids,  except  molten  metals,  are  relatively  poor  con- 
ductors of  heat,  while  the  conductivity  of  gases  is  very  small. 
However,  on  account  of  convection  primarily  and  radiation 
secondarily,  it  is  very  difficult  to  determine  the  conductivity 
of  liquids  and  gases. 

66. — Convection, — Convection  is  the  transfer  of  heat  by 
displacement  of  movable  media,  that  is,  the  carrying  of  heat 


TRANSFER  OF  HEAT  99 

INTERNAL  THERMAL  CONDUCTIVITY  OF  VARIOUS  MATERIALS.   (C)* 


Description 


3.t.u.   per     B.t.u.  per       Lb.  per 
24  hours  hour  cu.  ft. 


Air 

Air  Cell.  K  inch. 

.  .  Ideal  air  space 

.Asbestos   paper   and   air 

4.2 

0.175 

0.08 

spaces 

11.0 

0.458 

8.80 

Air  Cell.  1  inch.. 

.Asbestos   paper    and   air 

spaces 

12.0 

0.500 

8.80 

Aluminum 

.Cast 

24.000 

1000.000 

Ammonia  Vapor. 
Aqua  Ammonia  . 
Asbestos  Mill  Bd 

32°  F. 

3   19 

0   133 

0.21 
56.50 

75.90 

3.160 

. .  Pressed  asbestos— not  very 

20.00 

0.830 

61.00 

Asbestos  Paper. . 

.  Asbestos  and  organic  bind- 

12. 

0.500 

31.0 

Asbestos  Wood.. 

.  Asbestos  and  cement 

65.0 

3.700 

123.0 

Balsa  Wood 

.  Very  light  and  soft— across 

grain 

8.4 

0.350 

7.5 

Boiler  Scale 

305 

12.700 

Brass 

15.000 

625 . 000 

250. 

Brick 

.  Heavy 

120 

5.000 

131. 

Brick 

.Light,  dry 

.Salt 

84 

3.500 

115. 

Bnne 

27.1 

1.130 

73.4 

Cabot's  Quilt .  . . 

.  Eel  grass  enclosed  in  bur- 

lap 

7.7 

0.321 

16.0 

Calorax 

.  Fluffy  finely  divided  min- 

eral matter 

5.3 

0  221 

4  0 

Celite 

.  Infusorial  earth  powder. . . 

7.4 

0.308 

10  6 

Cement 

.  Neat  Portland,  dry 

150.0 

6  250 

170. 

Charcoal 

.  Powdered 

10.0 

0.417 

11.8 

Charcoal 

.  Flakes 

14.6 

0.613 

15  0 

Cinders 

.  Anthracite,  dry 

20.3 

0.845 

40.0 

Concrete 

125.0 

5  200 

136.0 

Concrete 

.  Of  fine  gravel 

109.0 

4.540 

124.0 

.Of  slag 

50.0 

43. 

2.080 
1.790 

94.5 

7.5 

Concrete 

.  Of  granulated  cork 

Copper 

50.000 

2083 . 000 

556.0 

Cork 

.  Granulated  J4-3/16  inch. . 

8.1 

0.337 

5.3 

Cork 

.Regranulate  1/ 16- J^  inch. 

8.0 

0.333 

10  0 

Corkboard 

.No  artificial    binder — low 

density 

6.7 

0  279 

6.9 

Corkboard 

.  No  artificial  binder — high 

density 

7.4 

0.308 

11.3 

7.0 
16.0 

0.292 
0.666 

'29'.  6' 

Cypress 

.  Across  grain 

Fibrofelt 

.  Felted  vegetable  fibers  .  .  . 

7.9 

0.329 

11.3 

Fire  Felt  Roll. . . 

.  Asbestos  sheet  coated  with 

15  0 
14.0 

0.625 
0.583 

43. e 
26.0 

Fire  Felt  Sheet.. 

.  Soft,  flexible  asbestos  sheet 

Flaxlinum 

.  Felted  vegetable  fibers  .  .  . 

7.9 

0.329 

11  .3 

Fullers  Earth .  .  . 

.Argillaceous  powder 

17.0 

0.708 

33.0 

Glass 

124.0 

5.160 

ISO  0 

Glass    .    . 

178.0 

600 
7.5 
62.0 
39.0 

7.420 
25.000 
0.313 
2.582 
1.630 

185.0 
166.0 
8.1 
115   0 
91.25 

Gravel 

Gravel 

.  Dry.  fine 

Ground  Cork  .  .  . 

7.1 
54.0 

5.9 
27.0 

0.294 
2.250 
0  246 
1.125 

9.4 

'ii'o 

44.0 

Hair  Felt 

Hard  Maple .... 

.  Across  grain 

Ice 

408 

17.000 

57.4 

Infusorial  Earth. 

.  Natural  blocks 

14.0 

0.583 

43.0 

Insule.x 

.Asbestos   and    plaster 

22.0 

0.916 

29.0 

Insulite 

7.  1 

0.296 

11.9 

.Cast 

7.740 

321.500 

450.0 

Iron 

.  Wrought 

11.600 

483 . 000 

485.0 

Kapok 

.Imp.     vegetable    fiber  — 
loosely  packed 

5.7 

0.238 

0.88 

Keystone  Hair .  . 

.Hair    felt    confined    with 

building  paper 

6.5 

0.271 

19.0 

Limestone 

.  Close  grain 

368 

15.300 

185.0 

Limestone 

.Hard 

214.0 

9.330 

159.0 

E.,    1926,    "Principles    of 

Refrigeration,"    Nickerson    S:    Coll 

•W.    II.    Motz,    M. 

ns 

Co.,    Chicago. 

100 


CORK  INSULATION 


INTERNAL   THERMAL   CONDUCTIVITY    OF    VARIOUS 
MATERIALS    {C)—Co7itmiied. 


B.t.u.   per 

B.t.u.  per 

Lb.  per 

Material 

Description 

24  hours 

hour 

cu.  ft. 

Soft 

100.0 

4.167 

113.0 

Linofelt 

Vegetable    fiber    confined 

with  paper 

7.2 

0.300 

11.3 

Lithboard 

Vlineral  wool  and  vegeta 

ble  fibers              ...    . 

9.1 
.      22.0 

0.379 
0.916 

Mahogany 

Across  grain 

34  0 

Marble 

Hard 

.   445 

18.530 

175.0 

Marble 

Soft                          

.    104 
.       6.6 

4.330 
0.275 

156  0 

Mineral  Wool 

Medium  Packed 

12.5 

Mineral  Wool 

Pelted  in  blocks 

.       6.9 

0.288 

18.0 

Oak 

Across  grain 

.      24.0 

1.000 

38.0 

Paraffin 

'Parowax,"  melting  point 

52°  C.             

.     38.0 
.     24.7 

1.582 
1.030 

56.0 

Petroleum 

55°F 

50.0 

Plaster  

.    132.0 
.     90 

5.500 
3.750 

105.0 

Plaster 

Ordinary  mixed 

83.5 

Plaster 

Board 

.      73 

3.040 

75.0 

Planer  Shavings. . . 

Various 

.      10.0 

0.417 

8.8 

Pulp  Board 

Stifif  pasteboard 

Powdered 

.      11.0 

0.458 

Pumice 

.      11.6 

0.483 

20.0 

Pure  Wool       

.        5.9 
.        5.9 

0.246 
0.246 

6.9 

Pure  Wool 

6.3 

Pure  Wool     

.        6.3 
.        7.0 
.      16.0 

0.263 
0.292 
0.667 

5.0 

Pure  Wool 

2  5 

Rice  Chaff 

10.0 

Rock  Cork 

Mineral  wool  and  binder- 

rigid 

.        8.3 

0.346 

21.0 

Rubber 

Soft     

.     45 
.      16.0 

7.875 
0.667 

94.0 

Rubber 

Hard,  vulc 

59.0 

Sand 

River,  fine,  normal 

.    188,0 

7.830 

102.0 

Sand 

Dried  by  heating 

.      54.0 

2.250 

95.0 

.    265 

11.100 

138.0 

Sawdust 

Dry 

.      12.0 

0.500 

13.4 

Sawdust 

Drdinary 

.      25.0 

1.040 

16.0 

Shavings 

3rdinary 

.      17.0 

0.707 

8.0 

.      14  0 

.      18.0 

0.583 
0.750 

8.55 

Slag  Wool 

15.0 

.      75 
.      17.0 

3.130 
0.707 

Tar  Roofing 

55.0 

Vacuum 

Silvered  vacuum  jacket. . 

0.1 

0.004 

Virginia  Pine 

Across  grain 

.      23.0 

0.958 

34.0 

Water 

Still,  32°  F 

.    100 

4.166 

62.4 

White  Pine 

Across  grain 

.      19.0 

0.791 

32.0 

Wool  Felt 

Flexible  paper  stock .... 

.        8.7 

0.363 

21.0 

from  one  point  or  object  to  another  by  means  of  an  outside 
agent,  such  as  air  or  water,  or  any  moving  gas  or  fluid.  The 
phenomenon  is  due  to  the  fact  that,  in  general,  Uquids  and 
gases  are  lighter  when  warm  than  when  cold.  Land  and  sea 
breezes,  trade  winds  and  ocean  currents  carry  great  quantities 
of  heat  from  one  place  on  the  earth  to  another;  while  the 
heating  of  buildings  by  hot  water  circulating  through  pipes, 
or  by  hot  air  furnaces,  is  another  familiar  application  of 
convection  currents. 

It  is,  at  best,  a  complicated  process  to  attempt  to  calculate 
heat  transfer  by  convection,  because  there  are  so  many  factors 
involved  that  are  incapable  of  accurate  determination.     Per- 


TRANSFER  OF  HEAT 


101 


haps  the  most  important  of  these  pertains  to  the  conditions 
that  exist  between  the  conducting  solid  material  and  the  gas 
or  liquid  in  contact  in  which  convection  occurs.  The  resist- 
ance to  heat  transfer  at  the  surface  of  a  solid  when  in  contact 
with  a  gas  or  liquid  is  known  to  be  important,  but  its  nature 
and  extent  is  not  generally  understood. 

(^  Fluids,  in  general,  conduct  heat  less  rapidly  than  is  com- 
monly supposed,  the  difficulty  of  considering  their  heat  con- 
chiction  separate  from  their  heat  convection  probably  account- 


In- 
side 
Cold 


FIG.   35.— TRANSFER  OF  HEAT  BY  CONVECTION. 

ling  for  this  misconception.  The  fact  is  important,  however, 
in  the  consideration  of  the  surface  or  contact  thermal  resist- 
ance between  solids  and  fluids ;  because  the  finite  layer  of 
fluid  in  actual  contact  with  a  soHd  is  always  at  rest,  and  a 
finite  thickness  next  adjacent  is  moving  very  slowly.  The 
resistance  of  this  stagnant  layer  of  fluid,  through  relatively  low 
conduction,  is  responsible  for  the  surface  resistance  to  heat 
transfer;  and  such  surface  resistance  in  any  example  must 
be  dependent  upon  the  actual  conditions  of  the  case. 

The    transfer    of    heat    by    evaporation    and    condensation    is 


102  CORK  INSULATION 

usually  classed  as  convection,  although  in  several  respects  it 
differs  widely  from  convection  as  just  discussed.  In  ordinary 
convection,  it  has  been  noted  that  the  surface  layer  of  fluid 
plays  an  important  part;  but  in  the  steam  boiler  the  finite 
layer  of  water  next  the  hot  boiler  wall  is  heated  and  vaporized, 
thus  absorbing  a  very  large  amount  of  heat.  Such  steam  is 
instantly  replaced  by  other  water  and  the  process  is  continued, 
a  procedure  distinctly  different  from  the  usual  convective 
heating  process  and  one  in  which  the  rate  of  heat  transfer  is 
much  higher.  By  drainage,  on  the  condenser  end  of  the 
system,  the  film  of  condensed  water  is  quickly  removed, 
which  differs  from  the  usual  transfer  by  convection. 

The  transfer  of  heat  by  evaporation  and  condensation  has 
a  definite  bearing  on  the  effect  of  moisture  in  insulating 
materials  and  in  air-space  construction. 

Thus,  in  general,  the  rate  of  heat  transfer  by  convection 
is  dependent  on  the  kind  of  fluid  in  contact,  the  temperature 
differences,  the  velocity  of  the  convecting  fluid,  the  character 
of  surfaces  (such  as  shape  and  roughness),  and  the  area  of 
the  surface. 

67. — Radiation.— Radiation  is  the  mode  of  transfer  of  heat, 
for  example,  from  the  sun  to  the  earth,  which  is  accomplished 
even  though  the  intervening  space  is  entirely  devoid  of  ordi- 
nary matter.  The  transfer  of  heat  by  radiation  is  effected  by 
wave  motion  exactly  similar  in  general  character  to  the  wave 
motion  that  constitutes  light,  these  waves  being  transmitted 
by  a  medium,  known  as  ether,  that  fills  all  space,  although, 
contrary  to  popular  belief,  considerable  obstruction  is  offered 
to  the  passage  of  these  waves. 

The  molecular  disturbance  in  a  hot  body  produces  a  com- 
motion in  the  immediate  adjacent  ether,  which  spreads  out  in 
all  directions  as  an  ether  wave  disturbance,  and  when  these 
waves  impinge  on  a  cool  body  they  produce  a  molecular  dis- 
turbance in  it.  In  a  word,  the  heat  energy  of  a  hot  body  is 
constantly  passing  into  space  as  radiant  energy  in  the  luminif- 
erous  ether,  and  becomes  heat  energy  again  only  when  and  as 
it  is  absorbed  by  bodies  upon  which  it  falls ;  and  energy  trans- 
mitted in  this  way  is  referred  to  as  radiant  heat,  although  it  is 
transmitted  as  radiant  energy  and  is  transferred  again   into 


TRANSFER  OF  HEAT 


103 


heat  only  by  absorption.  Radiant  heat  and  light  are  phys- 
ically identical,  but  are  perceived  through  different  avenues  of 
sensation;  radiations  that  produce  sight  when  received  through 
the  eye,  give  a  sensation  of  warmth  through  the  nerves  of 
touch.  The  sensation  of  warmth  felt  in  bright  sunlight  on  a 
cool  day  is  a  good  illustration  of  this  phenomenon. 


FIG.    36.— TRANSFER    OF    HEAT    BY    RADIATION— 
THE  RADIOMETER. 

The  rate  of  heat  transfer  by  radiation  depends  on  the 
characters  of  both  the  hot  radiating  and  the  cold  receiving 
surfaces  (the  reflecting  power  of  the  hot  surface  and  the 
absorbing  power  of  the  cold  surface),  the  temperature  differ- 
ences, the  relative  absolute  temperatures,  and  the  distance 
between  surfaces. 

The  blacker  an  object  the  more  heat  it  will,  in  general, 


104  CORK  INSULATION 

lose  by  radiation ;  non-metals  radiate  heat  at  a  much  more 
rapid  rate  than  metals  of  similar  surface ;  and  rough  surfaces 
radiate  heat  at  a  more  rapid  rate  than  smooth,  polished  sur- 
faces. Thus  stoves  and  radiators*  intended  to  give  out  heat 
should  present  a  non-metal  surface,  the  color  and  relative 
degree  of  smoothness  being  of  lesser  importance.  Metal  cook- 
ing utensils  should  be  tinned  or  nickeled  in  order  to  radiate  as 
little  heat  as  possible.  A  brightly  tinned  hot  air  furnace  pipe 
may  lose  less  heat  by  radiation  than  when  covered  with  thin 
asbestos  paper,  because  the  surface  of  the  non-metallic  asbes- 
tos paper  radiates  heat  more  rapidly  than  the  bright  tin. 

The  heat  radiated  to  a  body  may  be  partly  rejected,  ab- 
sorbed, or  transmitted  through  the  body.  The  capacity  of  a 
surface  to  absorb  radiant  energy  depends  both  on  the  lack  of 
polish  of  the  surface  and  the  nature  of  the  material.  Lamp- 
black is  the  best  absorber  of  radiant  energy  and  polished  brass 
is  the  poorest.  In  cold  climates  dark  clothes  are  worn  because 
they  absorb  and  transmit  the  greatest  proportion  of  radiant 
energy,  while  in  hot  climates  white  clothes  are  preferred 
because  they  reject  radiant  energy  to  the  maximum  extent. 
)  Tt  has  been  noted  that  if  no  heat  is  supplied  or  taken  away, 
'  aTT  surfaces  in  an  enclosure  come  to  the  same  temperature ; 
the  rate,  however,  at  which  this  equalization  takes  place  de- 
pends on  the  radiating  and  the  reflecting  powers  of  such 
surfaces.  Thus  the  temperature  of  a  surface  may  be  higher 
than  the  air  adjacent  to  it.  A  wall  in  direct  sunlight  is  often 
a  good  many  degrees  warmer  than  the  atmosphere,  which 
fact  is  important  in  the  consideration  of  insulation  for  build- 
ings since  the  temperature  of  the  outside  wall  surface — not 
that  of  the  air — helps  determine  the  heat  leakage. 

The  Stefan-Baltzmann  radiation  law  for  calculating  heat 
losses  is  as  follows: 

H2=R  A  h  (T^y—iT^y 
where  Hj  is  the  total  heat  radiated  in  a  given  time  in  B.t.u., 
R  is  a  constant  (see  accompanying  table  for  values  for  various 
radiating  materials),  A  is  the  area  of  the  radiating  surface 
in  square  feet,  h  is  the  time  in  hours,  Tj  is  the  higher  tem- 

*It  must  be  remembered  that  heat  is  transferred  by  conduction,  convection  and 
radiation, — not  by  radiation  alone, — and  that  heat  transfer  by  radiation  is  spoken  of 
here,   which  is  of  secondary  importance  to  the   total   heat  transfer. 


TRANSFER  OF  HEAT  105 

perature  absolute  in  degrees  F.  and  T2  is  the  lower  tempera- 
ture absolute  in  degrees  F.  (Absolute  temperature  is  460 
degrees  below  zero  F.,  or  273  degrees  below  zero  C.)  If  large 
temperature  differences  are  not  involved,  then  use  the  for- 
mula : 

H^=R  A  h  (T)* 

where  T  is  the  absolute  temperature  in  degrees  F. 

TABLE  OF  STEFAN-BALTZMANN   CONSTANTS   (R). 

Material  Constant   (R) 

Lampblack     0.900 

Smooth  glass   0. 1 54 

Dull     brass     0.0362 

Dull    steel    plate    0.338 

Slightly  polished  copper    0.0278 

Dull  oxidized   wrought   iron    0. 1 54 

Clean,    bright    wrought    iron    0.0562 

Highly    polished    wrought    iron     0.0467 

Polished    aluminum    plate     0.053 

Water     0.112 

Ice     0.106 

^68. — Flow  of  Heat. — Generally  the  transfer  of  heat  takes 

place  by  all  three  processes — condviction,  convection  and  radi- 
ation— simultaneously.  Thus  heat  is  distributed  throughout 
a  room  from  a  hot  stove  or  furnace  partly  by  radiation,  prin- 
cipally by  convection  currents  of  air  and  to  a  slight  extent 
by  conduction.  Such  a  body  is  said  to  emit*  heat,  and  the 
rate  at  which  a  body  emits  heat  depends  upon  its  excess  of 
temperature  above  its  surroundings,  upon  the  extent  and  char- 
acter of  the  body  and  its  surface,  upon  the  nature  of  the 
surrounding  gas  or  liquid,  upon  the  freedom  of  motion  of  the 
surrounding  fluid,  and  upon  the  nature  of  surrounding  bodies. 
Thus  it  is  evident  that  many  variables  enter  into  the 
determination  of  heat  transfer  by  radiation  and  by  convection. 
Reliable  experimental  information  is  lacking,  because  it  is 
very  difficult  to  ascertain  the  exact  effect  of  each.  However, 
the  engineer  is  concerned  primarily  with  the  combined  trans- 
ference of  heat  by  conduction,  convection  and  radiation.  The 
heat  transferred  by  convection  and  radiation  may  be  deter- 
mined by  experimentation.  The  combined  coefficient,  or  rate, 
of  this  heat  transfer  by  convection  and  radiation  is  the  heat 
given  off  or  absorbed  per  square  foot  of  surface,  per  hour,  per 
degree  of  temperature  difference  F.     In  the  case  of  cold  stor- 

*This  term  is  variously  used  to  indicate  the  emission  of  heat  by  a  body  by  radia- 
tion only,  by  radiation   and  convection,  and  by  all  three  methods  combined. 


106  CORK  INSULATION 

age  wall  insulation,  this  temperature  difference  would  be  the 
difference  between  the  temperature  of  the  surface  of  the  wall 
and  the  average  temperature  of  the  surrounding  air ;  while 
the  velocity  of  the  air  across  the  surface  of  such  wall  must 
affect  the  coefficient,  or  rate,  of  heat  transfer  by  convection 
and  radiation. 

The  values  for  the  coefficient  of  convection  and  radiation 
for  various  materials  undeY  still  air  conditions  are  given  in  the 
accompanying  table,  and  are  based  upon  experiments  made  at 
the  Engineering  Experiment  Station  of  the  University  of 
Illinois. 

This  coefficient  is  generally  denoted  by  the  symbol  K^, 
and  is  called  the  coefficient  of  radiation  and  convection  for 
inside  surfaces.  In  an  actual  plant,  the  outside  walls  are 
exposed  to  the  more  rapid  movement  of  the  air,  so  that  the 
coefficient  of  radiation  and  convection  is  larger  for  the  outside 
surfaces.  The  symbol  for  this  coefficient  is  Kg,  and  it  is,  in 
general,  2.5  to  3  times  the  inside  wall  coefficient  K^,  due  to 
the  greater  velocity  of  the  outside  air.  Thus,  as  a  general 
rule,  the  value  of  the  outside  coefficient,  Kj,  may  be  con- 
sidered to  be  three  times  the  inside  coefficient,  K^. 

COEFFICIENTS   OF   RADIATION   AND   CONVECTION    (Kl)    IN   B.t.u.   PER 
HOUR  PER  DEGREE  TEMPERATURE  DIFFERENCE  F. 

Material  Coefficient  Ki 

Brick    wall    1.40 

Concrete   1.30 

Wood     1.40 

Corkboard     1.25 

Magnesia  board    1.45 

Glass    2.00 

Tile  plastered  on  both  sides   1.10 

Asbestos    board    1.60 

Sheet  asbestos   1.40 

Roofing     1.25 

69. — Total  Heat  Transfer. — In  its  simplest  form,  total  heat 
transfer  is  the  heat  passing  into,  through  and  out  of  a  single 
wall  of  given  area.  If  the  surface  temperatures  and  the 
temperatures  in  the  surrounding  air  are  taken,  the  total  heat 
transmission  may  be  separated  into  internal  and  external  con- 
ductivity, the  external  conductivity  being  sometimes  called 
"surface  effects."  In  the  case  of  a  good  insulator,  as  used  for 
cald  storage  rooms,  internal  conduction  is  the  essential  factor; 
while  in  the  case  of  a  poor  insulator,  as  the  metal  in  a  boiler 
tube,  good  conduction  is  necessary  and  surface  transmission 


TRANSFER  OF  HEAT 


107 


is  all-important.  Between  these  extreme  conditions,  the  rela- 
tive importance  of  conduction  and  surface  transmission  (con- 
vection and  radiation)  varies  with  each  case  considered.  In 
determining  the  total  transmission  of  three-inch  corkboard 
insulation  in  still  air,  an  error  of  about  ten  per  cent  is  intro- 
duced if  the  surface  effects  on  both  sides  are  disregarded ; 
while  in  the  case  of  a  single  thickness  of  brick,  the  resistance 


Ou-t 


>       ±, 


Kz 


c-X--? 


± 

COLD 

± 

-t 

FIG.  37,— HEAT  TRANSFER  THROUGH  A  WALL. 


to  the  flow  of  heat  of  the  two  surfaces  is  about  eight  times 
the  internal  resistance  of  the  brick.  In  general,  the  better  the 
substance  as  an  insulator,  the  less  is  the  error  due  to  dis- 
regarding surface  effects. 

It  has  been  observed  that  heat  may  be  transmitted  from  a 
region  of  high  temperature  through  a  wall  into  a  region  of 
lower  temperature  by  means  of  conduction,  convection  and 
radiation.  The  accompanying  figure  shows  graphically  the 
transfer  of  heat  from  the  outside  through  a  wall  to  the  inside. 


108  CORK  INSULATION 

It  will  be  seen  that  the  heat  passes  by  convection  and  radia- 
tion from  the  surface  of  a  warm  body  at  to  degrees  F.  to  the 
outside  surface  of  the  wall,  where  it  is  absorbed  by  that 
surface,  conducted  through  the  wall  and  then  given  off  by  the 
inside  surface  of  the  wall  by  means  of  convection  and  radia- 
tion to  the  surface  of  the  cold  body  at  t  degrees  F. 

The  heat  is  conducted  through  the  wall,  due  to  the  tem- 
perature difference  between  the  outside  and  the  inside  sur- 
faces of  the  wall,  the  temperature  at  the  outside  surface  being 
noted  as  t^  and  the  temperature  at  the  inside  surface  as  tg. 
The  amount  of  heat  conducted  through  this  wall,  as  previously 
mentioned,  would  depend  on  the  internal  thermal  conduc- 
tivity (C)  and  the  thickness  of  the  wall  (X).  Since  heat  is 
conducted  through  the  wall  because  of  temperature  differ- 
ences at  the  surfaces  of  the  wall,  it  is  proper  to  say  that  this 
temperature  difference  exists  within  very  thin  layers  of  air 
at  such  surfaces.  On  the  outside  of  the  wall  in  the  figure, 
this  is  represented  by  the  difference  between  the  tempera- 
ture of  the  outside  air,  to,  and  the  temperature  at  the  outside 
surface,  t^,  and  on  the  inside  this  is  represented  by  the  differ- 
ence between  the  temperature  of  the  inside  surface,  tj,  and 
the  temperature  of  the  inside  air,  t. 

The  total  amount  of  heat  passing  from  the  warm  body 
on  the  outside  to  the  cold  body  on  the  inside  depends  on  the 
combined  conduction,  convection  and  radiation  effects.  The 
quantity  of  heat  transferred  from  the  outside  air  to  the  wall 
depends  on  the  coefficient  of  the  combined  radiation  and 
convection,  K^,  sometimes  called  the  surface  coefficient,  and 
the  temperature  of  the  outside  air,  to,  and  the  temperature  at 
the  outside  surface,  t^.  The  heat  given  off  by  the  inside  sur- 
face of  the  wall  to  the  inside  air  will  depend  on  the  coefficient 
of  the  combined  radiation  and  convection  for  such  inside 
surface,  K^,  and  the  temperature  of  the  inside  surface,  t^, 
and  the  temperature  of  the  inside  air,  t. 

Thus,  the  total  heat  transmission  from  the  surface  of  the 
outside  hot  body  to  the  surface  of  the  inside  cold  body  will 
depend  on  the  combined  heat  transfer  coefficient,  K,  and  the 
temperature  of  the  outside  air,  to,  and  the  temperature   of  the 


TRANSFER  OF  HEAT  109 

inside   air,   t.      From   this   analysis,   the  value  of    the   unit   total 
heat  transfer  coefficient,  K,  may  be  expressed  as  follows: 

1 
K= 


1        X        1 
K,       C       K^ 


From  til  is  formula,  it  will  be  noted  that  the  unit  total  heat 
transfer  coefficient,  K,  in  B.t.u.  per  hour,  per  degree  tempera- 
ture difference  F.,  for  a  given  wall,  depends  on  the  combined 
convection  and  radiation  coefficient  for  the  inside  and  outside 
surfaces,  K^  and  K,,  respectively,  the  thickness  of  the  waW, 
X,  and  the  internal  conductivity  of  the  material,  C.  The 
values  of  the  conductivity,  C,  for  various  materials  and  the 
values  of  the  coefficients  of  the  combined  inside  convection 
and  radiation,  K^,  are  given  in  the  accompanying  tables. 
The  values  of  K2,  in  general,  may  be  taken  as  three  times  K^. 
In  the  case  of  a  solid  wall  made  up  of  layers  of  different 
materials,  in  intimate  contact,  having  different  conductivities, 
Ci,  Co,  C3,  etc.,  of  various  thicknesses,  X^,  Xo,  X3,  etc.,  re- 
spectively, the  foregoing  formula  becomes  : 


K=: 


Suppose  it  is  desired  to  determine  how  much  heat  per 
hour  is  transmitted  through  an  outside  heavy  brick  wall  18 
inches  thick,  20  feet  high,  and  25  feet  long,  when  the  outside 
temperature  is  80°  F.  and  the  inside  temperature  is  20°  F.  From 
the  tables,  C  equals  5,  K^  equals  1.4,  and  K2  equals  three  times 
1.4,  or  4.2.  Thus  the  heat  transmission  coefficient  is  found  as 
follows : 


1 

Xt 

X, 

-^ — 
C2 

Xs 

-H — 
C3 

-+etc 

■h 

1 

1 

K= =0.2196 

1 


—     i     -      [     — 
1.4     1     5      J      4.2 


The  area.  A,  is  equal  to  20x25,  or  500  square  feet,  and  t^ 
equals  80°  F,  and  t^  equals  20°  F,  The  total  heat  transfer  is 
therefore : 


110  CORK  INSULATION 

H=K  A  (.U—U) 
r=0.2196X500X(80°-20°) 
=:6588  B.t.u.  per  hour. 

Suppose  it  is  desired  to  determine  the  heat  transmission  of 
a  similar  brick  wall  of  equal  thickness  insulated  with  4  inches 
of  corkboard  applied  directly  to  the  wall  in  ^-inch  Portland 
cement  mortar  and  finished  with  Portland  cement  plaster 
J^-inch  thick.  From  the  table,  K^  (for  plastered  surface) 
equals  1.1,  C^  equals  5,  X^  equals  18,  Co  equals  0.308,  X2  equals 
4,  C3  (for  1-inch  thick  Portland  cement)  equals  6.25,  X3  equals 
1,  and  Ko  equals  4.2.  Thus  the  heat  transmission  coefficient 
for  this  composite  wall  is  found  as  follows : 

1 

K= 1=0.05588 

1         f    18       4  ill 

1.10      L     5      .308      6.25      J       4.2 

The  total  heat  transfer  is  therefore : 

H=K  A  (ti— ti) 
=0.05S88X500X(80°-20'') 
=  1676.4  B.t.u.  per  hour. 

Suppose  it  is  desired  to  determine  the  heat  transmission 
of  a  similar  brick  wall  of  equal  thickness  insulated  with  four 
2-inch  air  spaces  formed  by  four  double  layers  of  1-inch  white 
pine.  From  the  tables,  K^  (for  inside  brick)  equals  1.4,  K^'  (for 
each  of  8  inside  surfaces  of  wood)  equals  1.4,  C^  (for  brick) 
equals  5,  X^  (for  brick)  equals  18,  Cg  (for  white  pine)  equals 
0.791,  X2  (8  layers  wood)  equals  8,  K,  (for  outside  brick) 
equals  4.2.    The  value  of  K  is  then  as  follows : 

1 
K= =0.04906 


L     1.4      J  L    5  0.791    J      4.2 


1.4 

The  total  heat  transfer  is  therefore 

H=K  A  (ti— t.) 
=0.04906X500X  (80^-20°) 
=  1471.8  B.t.u.  per  hour. 

It  will  be  noticed  at  once  that  an  18-inch  brick  wall  in- 
sulated with  four  2-inch  air  spaces  formed  by  four  double  layers 
of  1-inch  white  pine  shows,  by  this  method  of  computation,  a 


I 


TRANSFER  OF  HEAT  111 

lower  total  heat  transfer  than  a  similar  brick  wall  insulated 
with  4  inches  of  corkboard.  Experience  teaches  that  the  fig- 
ures just  shown  are  not  accurate  and  the  same  problem  is 
solved  by  a  different  method  in  the  next  Article. 

70. — Air  Spaces. — It  should  be  especially  noted  here  that 
a  high  vacuum  is  necessary  to  appreciably  lower  the  normal 
rate  of  heat  transfer  by  convection  across  air  spaces,  and  that 
such  rate  increases  very  appreciably  as  the  temperature  dif- 
ferences increase.  Also,  that  the  amount  of  heat  passing 
across  an  air  space  by  radiation  is  very  much  enlarged  when 
there  is  a  large  temperature  difference  between  radiating  and 
receiving  surfaces,  for  it  will  be  remembered  that  the  rate  of 
heat  transfer  by  radiation  is  proportional  to  the  difference 
between  the  fourth  powers  of  the  absolute  temperatures  of 
the  surfaces  involved,  subject  only  to  correction  for  losses  due 
to  imperfections  in  radiating  and  absorbing  surfaces. 

The  United  States  Bureau  of  Standards,  in  the  accompany- 
ing table,  gives  some  interesting  and  valuable  data  on  the 
heat  conduction  of  air  spaces,  in  which  X  is  the  width  of  the 
air  spaces  in  inches  and  C  is  the  heat  conductivity  in  B.t.u. 
per  square  foot,  per  degree  difference  F.,  per  inch  thickness, 
per  hour,  from  which  table  it  should  be  especially  noted  that 
the  thermal  conductivity  of  air  spaces  is  not  proportional  to 
the  thickness  of  the  spaces. 

THERMAL    CONDUCTIVITY    OF   AIR    SPACES    (C)    IN    B.t.u.  PER    HOUR, 
PER  DEGREE  DIFFERENCE  F.,  PER  INCH  THICKNESS. 
Thickness   (X)                                                                                         Conductivity   (C) 

^-inch     . 0.2625 

j4-inch     0.3375 

H-inch     0.4083 

^-inch     0.4833 

f^-inch     0.5667 

^-inch     0.6833 

^-inch     0.8333 

l-inch     0.91 67 

2-inch    1-7917 

3-inch    2.5833 

The  determination  of  the  heat  transmission  of  an  18-inch 
brick  wall  insulated  with  four  2-inch  air  spaces  formed  by  four 
double  layers  of  1-inch  white  pine,  based  on  the  thermal  conduc- 
tivities of  air  spaces  as  determined  by  the  Bureau  of  Stand- 
ards, becomes  a  different  problem  from  that  presented  in  the 
preceding  Article.  From  the  tables,  K^  (for  inside  wood) 
equals  1.4,  C^   (for  brick)   equals  5,  C^   (for  2-inch  air  space) 


112  CORK  INSULATION 

equals  17917,  C3  (for  white  pine)  equals  0.791,  X^  equals  18, 
X2  equals  4,  X3  equals  8  and  Kg  equals  4.2.  The  value  of 
K  is  then  as  follows : 

1 
K= =0.05915 

1       J    18         4  8        1        1 

TJ     1     5       1.7917     0.791     J       4.2 
The  total  heat  transfer  is  therefore : 


H=K  A  iU—U) 
=0.05915X500X(80°— 20°) 
=  1774.5  B.t.ii.  per  hour. 

71. — Heat  Transfer  by  Conduction  Only.-^It  will  be  noted 
that  the  heat  that  passes  through  an  insulated  wall  depends 
mostly  upon  the  internal  thermal  conductivity  of  the  mate- 
rials that  compose  the  wall,  and  that  the  resistance  to  the 
flow  of  heat  at  the  surface  (convection  and  radiation)  but 
slightly  reduces  the  total  heat  transfer.  This  may  be  seen 
by  calculation  from  the  example  of  the  18-inch  brick  wall 
insulated  with  4  inches  of  corkboard,  as  follows : 

1 

K= =0.0597 

18       4  1 

5     .308     6.25 

The  heat  transfer  (by  conduction  only)  is  therefore: 

_     :  ■;    1?'.H=K  A  (ti— tz) 

=0.0597x500X(80°-20°) 
=  1791   B.t.u.  per  hour. 

Thus  It  is  seen  that  the  increase  in  heat  flow  in  this 
example  due  to  neglecting  the  surface  effects  is  but  6.8%, 
under  the  normal  conditions  assumed ;  and  for  practical  pur- 
poses, in  connection  with  the  computation  of  refrigeration 
losses  due  to  heat  leakage,  the  following  formula  is  followed : 
A     (t.-t=) 


I 

I 


H: 


Xi     X2     X3 

Ci         C:         C3 


The  internal  heat  conductivities  available  for  the  deter- 
mination of  heat  losses  by  calculation  were,  for  the  most 
part,  secured  under  favorable  conditions,  in   testing  labora- 


TRANSFER  OF  HEAT  113 

tories;  and  much  practical  experience  with  cold  storage  in- 
sulation and  refrigeration  teaches  that  the  results  obtained 
by  computation  are  about  25%  lower  than  is  safe  to  expect 
in  actual  service  under  plant  working  conditions. 

72. — Heat  Loss  Through  Insulation. — The  internal  con- 
ductivity of  various  insulating  materials  depends,  in  general, 
upon  the  structure  and  density  of  the  material ;  and  since 
the  conductivity  of  still  air  is  very  low,  probably  because  of 
the  very  loose  arrangement  of  the  molecules,  then  a  material 
containing  a  large   percentage   of  "dead  air"   will   transfer   a 


FIG.   3S.— CORK  UNDER  POWERFUL  MICROSCOPE,   SHOWING  SEALED  AIR 
CELL  CONSTRUCTION. 

minimum  amount  of  heat.  But  to  keep  air  still,  to  keep  it 
from  circulating,  even  when  it  is  confined,  is  difficult,  espe- 
cially when  it  is  recalled  that  heat  applied  to  the  surface  of 
one  side  of  a  compartment  containing  air  will  warm  up  that 
surface,  the  heat  will  be  transmitted  in  more  or  less  degree 
through  the  wall  to  the  air  on  the  inside,  it  will  be  taken  up 
by  the  particles  of  air  in  contact  therewith,  and  warm  air 
being  at  once  lighter  than  cold  air  it  will  rise  and  be  replaced 
by  cold  air.  Thus  the  heat  is  quickly  and  effectively  car- 
ried across  the  air  space  to  the  wall  on  the  other  side,  by 


114  CORK  INSULATION 

convection,  and   by  conduction   passes   through   the  opposite 
wall  to  the  space  beyond. 

An  automobile  can  attain  a  greater  speed  on  a  two  mile 
track  than  it  can  attain  on  a  quarter  mile  track.  Similarly, 
air  can  attain  a  greater  velocity  in  a  large  space  than  it 
can  in  a  small  one.  Thus  this  principle  is  one  of  the  two 
main  guides  in  the  selection  of  an  efficient  insulating  material. 
First,  the  material  must  contain  air  in  the  very  smallest  pos- 
sible units,  such  as  atoms,  so  that  convection  is  reduced  to 
a  minimum ;  and  since  these  atoms  of  air  must  each  be  con- 
fined, a  material  must  be  selected  that  is  very  light  and  of 
little  density  so  that  conduction  is  also  reduced  to  a  mini- 
mum. Secondly,  such  material  must  at  the  same  time  be 
impervious  to  moisture,  so  that  its  initial  ability  to  retard 
heat  will  prevail  in  service.  Such  a  material  will  be  as  effi- 
cient from  the  standpoint  of  heat  transfer  as  it  is  possible 
to  obtain ;  that  is,  a  very  light  material  containing  myriads 
of  microscopic  air  cells,  each  cell  sealed  unto  itself.  A  mate- 
rial of  such  character  is  cork,  the  outer  bark  of  the  cork  oak  tree, 
native  of  the  Mediterranean  basin. 


CHAPTER  X. 

DETERMINATION    OF   THE   HEAT    CONDUCTIVITY 
OF  VARIOUS  MATERIALS.* 

73. — Methods  Employed. — It  is  a  complicated  as  well  as 
an  expensive  procedure  to  determine  with  any  degree  of 
accuracy  the  heat  conductivity  of  given  materials. f  In  spite 
of  this  fact,  a  great  many  experiments  and  tests  have  been 
made  over  a  period  of  many  years ;  but  in  the  absence  of 
any  standard  in  apparatus  or  uniformity  of  procedure,  the 
results  have  varied  so  much  as  often  to  be  of  no  real  value 
whatever. 

Most  common  of  the  test  methods  employed  are : 

(a)  Ice-box  Method. 

(b)  Oil-box  Method. 

(c)  Hot-air-box  Method. 

(d)  Cold-air-box  Method. 

(e)  Flat-plate    (or    Hot-plate)     Method. 

74. — The  Ice-box  Method. — The  most  common  of  all 
methods  of  comparing  the  heat  insulating  value  of  two  mate- 
rials has  been  by  the  use  of  two  identical  cubical  metal  boxes 
covered  with  the  materials  to  be  tested,  each  filled  with  ice, 
and  observing  the  rate  at  which  the  ice  melts.  Since  it  is 
difficult  to  keep  the  entire  box  at  32°  F.,  even  though  con- 
taining ice,  this  method  may  lead  to  inaccurate  results  even 
as  a  comparatk'c  test  of  two  materials.  As  a  method  of  test- 
ing any  one  material,  it  is  far  too  unreliable  to  be  of  any 
practical  value  whatever. 

75. — The  Oil-box  Method. — The  oil-box  method  of  com- 
parative   testing   consists    in    covering    two    identical    cubical 


*For  a  comprehensive  treatment  of  heat  transmission,  consult  "Heat  Transmis- 
sion of  Insulating  Materials,"  in  eleven  parts,  published  by  The  American  Society 
of  Refrigerating  Engineers,  37  W.   39th  St.,  New  York   City.      Price,  $2.50. 

fFor  a  comprehensive  treatment  of  methods  to  be  employed  in  testing  insulating 
materials,  consult  "An  Investigation  of  Certain  Methods  for  Testing  Heat  Insulators," 
by  E.  F.  Grundhofer,  The  Pennsylvania  State  College  Engineering  Experiment  Station 
Bulletin  No.  33.     Price,  25  cents.     Address:     State  College,  Pa. 

115 


116 


CORK  INSULATION 


metal  boxes  with  the  materials  to  be  tested,  each  filled  with 
mineral  oil  and  the  oil  surrounding  an  electrical  heater  and 
an  agitator.  By  varying  the  heat  supplied,  any  desired  dif- 
ference in  temperature  may  be  maintained  between  the  con- 
tents of  the  boxes  and  the  surrounding  air  of  the  room.  By 
measuring  the  electrical  input  by  ammeters  and  voltmeters, 
the  amount  of  heat  lost  through  the  respective  materials  under 
test  can  be  determined  by  calculation.  Inaccuracies  occur 
due  to  uncertainty  of  the  temperature  at  the  top  of  the  box 
and  loss  of  heat  through  agitator  rod,  box  supports,  evap- 
oration  of   oil    and   conduction    through    overflow   pipe.      For 


I 


J 


FIG.   39.— THE   ICE-BOX  METHOD   OF  TESTING   HEAT  TRANSMISSION'. 


the  comparative  testing  of  two  materials  of  equal  thickness, 
the  results  are  reasonably  accurate;  but  as  a  method  of  test- 
ing any  one  material  the  results  will  usually  be  too  high,  and 
unreliable. 

76. — The  Hot-air-box  Method. — The  hot-air-box  method 
of  testing  consists  of  a  cubical  box  constructed  wholly  of  the ; 
material  to  be  tested,  with  only  such  light  wooden  reinforcing 
as  may  be  required  for  strength  or  rigidity.  Inside  the  box 
is  placed  an  electrical  heater  and  an  electrical  fan,  which  per- 
mits of  a  uniform  box  temperature  maintained  at  any  desired 
temperature  difference  between  the  air  in  the  box  and  the 
surrounding  outside  air.  By  measuring  the  electrical  input, 
the  amount  of  heat  lost  through  the  material  under  test  can 
be  determined  b}'  calculation,  as  in  the  case  of  the  oil-box 


I 


HEAT  CONDUCTIVITY 


117 


method,  but  the  inaccuracies  are  reduced,  by  comparison,  to 
the  loss  of  heat  through  the  box  supports,  and  are  corre- 
spondingl}^   more  reliable.     This  method  of  testing  has  con- 


FIG.  40.— THE  OIL-BOX  METHOD  OF  TESTING  HEAT  TRANSMISSION. 

siderable  merit,  and  can  be  used  with  fairly  good  results  as 
a  method  of  testing  any  one  material  alone. 

77. — The  Cold-air-box  Method. — The  cold-air-box  method 

t  T 

I 


1\. rzj .„ 


FIG.  41.— THE  HOT-AIR-BOX  METHOD  OF  TESTING  HEAT  TRANSMISSION. 

of  testing  consists  in  the  substituting  for  the  heater  and  the 
fan  in  the  hot-air-box  method,  a  container  of  cracked  ice  sus- 
pended inside  the  cubical  test  box  near  the  top.     The  air  in 


118 


CORK  INSULATION 


the  test  box  will  be  maintained  at  a  lower  temperature  than 
the  outside  room,  and  since  the  amount  of  heat  required  to 
melt  one  pound  of  ice  is  definitely  known,  the  amount  of 
heat  lost  through  the  walls  of  the  test  box  may  be  determined 
by  weighing  the  water  resulting  from  the  melting  of  ice  and 
carried  outside  of  the  box  through  a  small  rubber  tube. 

The  results  are  reasonably  reliable  since  the  suspended 
container  of  cracked  ice  sets  up  a  natural  circulation  of  air 
within  the  test  box  and  keeps  it  at  a  very  nearly  uniform 
temperature. 


FIG.    42.— THE    COLD-AIR-BOX    METHOD    OF   TESTING    HEAT 
TRANSMISSION. 

78.— The   Hot-plate   Method.— The   hot-plate   method   has! 
probably  been  most  widely  used  by  investigators,  including! 
the   United   States    Bureau    of    Standards,   to   determine   the| 
relative    conductivity    of    insulating    materials.      The    inaccura- 
cies in  this  method,  for  absolute  conductivity  determination, 
lie  in  the  determination  of  the  heat  loss  from  the  edges,  which 
is  ordinarily  considerable,  and  the  uncertainty  of  the  contact 
between  the  material  and  the  plates. 

The  method  consists  of  an  electrically  heated  plate  placed 
between  two  sheets  of  the  material  to  be  tested,  and  outside 
of  these  sheets  are  placed  two  hollow  plates  cooled  by  circu- 
lating water.  By  measuring  the  electrical  input,  the  amount 
of  heat  lost  through  the  insulating  materials  can  be  deter- 
mined by  calculation.     The  temperature  difference   between 


I 


HEAT  CONDUCTIVITY 


119 


the  hot  and  the  water-cooled  plates  is  measured  by  thermal 
junctions.  Knowing  these  factors,  also  the  area  and  the 
thickness,  the  relative  conductivity  of  the  materials  under  test 
may  be  computed  with  precision. 

An  instrument  of  this  general  character,  which  shows  re- 
finements over  previous  apparatus,  has  lately  been  designed 
and  constructed.  The  hot  plate  consists  of  two  5^-inch  cop- 
per plates   12  inches  square,  between   which  are  the  heating 


FIG.  43.— THE  HOT-PLATE  METHOD   OF  TESTING  HEAT  TRANSMISSION- 
GENERAL  VIEW   OF   THERMAL    CONDUCTIVITY   APPARATUS,    8-IN. 
SQUARE. 


coils  consisting  of  nichrome  resistance  ribbon  wound  with 
even  spacing  on  a  slate  core  and  insulated  from  the  copper 
plates  by  two  sheets  of  mica  bond,  /n  order  to  minimize  the 
loss  of  heat  from  the  edges  of  the  hot  plate,  each  copper  plate 
is  divided  into  an  inner  test  area  8x8  inches  and  an  outer 
guard  ring.  A  compensating  winding  for  furnishing  auxiliary 
current  is  wound  around  the  outer  edges  of  the  plate,  to 
prevent  the  lateral  flow  of  heat  from  the  inner  test  area  to 
the  outer  guard  ring,  a  1/16-inch  air  space  being  left  between 


120 


CORK  INSULATION 


the  areas  and  the  areas  being  held  in  place  by  four  pieces 
of  Advance  wire  soldered  to  the  copper  plates. 

By  the  use  of  a  galvanometer,  the  inner  area  and  the 
outer  guard  ring  are  kept  at  the  same  temperature,  this  con- 
dition being  indicated  by  a  zero  reading,  and  under  which 
condition  it  is  assumed  that  no  heat  flows  from  the  8x8  inch 


I      MAM 


/  /  /  ^  o^/ 


-  EDGE  INSULATION 


■TBsrs/ifiPLes 


FIG.    44.— DIAGRAMMATIC   SKETCH    OF   APPARATUS    FOR   THE   PLATE 

METHOD    OF   MEASURING   THE   THERMAL    CONDUCTIVITY   OF 

MATERIALS. 

inner   portion    of   the    test   area   to   the   outer   portion    of   the 
test  area  or  guard  ring. 

Direct  current  from  a  generating  set  is  supplied  to  the 
main  heating  grid  and  also  to  the  auxiliary  guard  ring  cir- 
cuit; and  to  prevent  any  variation  in  current  due  to  voltage 
fluctuation,  a  ballast  tube,  similar  to  that  used  with  radio  sets, 
is  placed  in  the  main  line  and  automatically  keeps  the  current 
constant  to  the  main  heating  grid. 


HEAT  CONDUCTIVITY 


121 


FIG.    45.— DETAILS    OF    HEATING    PLATE    FOR    THERMAL    CONDUCTIVITY 

APPARATUS. 
(A)    Copper    plates.      (B)    Micanite   insulation.      (C)    Fibre   board — main   heater.      (D) 
Fibre    board — edge     heater.       (E)     Constantan     ribbon     1-16-in.     No.     36.     (F)     Brazed 
joints.       (G)     Steel    pins    for    suspension.       (H)     Copper    leads    to    main    heater.       (J) 
Brass   screws.      (K)    Copper   leads   to   edge   heater. 


Gua^<(R."J  Heirr^jCo'l 


Haii  Htar,„j  Ctil 


FIG.  -46.— ARRANGEMENT  OF  ELECTRICAL  CONNECTIONS  TO  THERMO- 
JUNCTIONS. 


122  CORK  INSULATION 

79. — Tests  by  Various  Authorities  on  Many  Materials. — 

Probably  the  most  comprehensive  and  the  most  widely  ac- 
cepted data*  on  the  rate  of  heat  flow  through  most  of  the 
materials  with  which  an  engineer  has  to  deal  is  given  in 
"Results  of  Tests  to  Determine  Heat  Conductivity  of  Various 
Insulating  Materials,"  by  Charles  H.  Herter,t  being  the  ninth 
section  of  the  "Report  of  Insulation  Committee"  of  the  Amer- 
ican Society  of  Refrigerating  Engineers,  published  in  the  Jan- 
uary, 1924,  number  of  "Refrigerating  Engineering."  The  com- 
plete "Report  of  Insulation  Committee,"  in  eleven  sections, 
is  now  available  in  data  pamphlet  form  from  the  American 
Society  of  Refrigerating  Engineers,  New  York  City  (Price, 
$2.50). 

In  his  report,  Mr.  Herter  says,  in  part: 

The  original  program  merely  called  for  a  "Summary  of  Test 
Results,"  with  a  tabulation  giving  but  one  recommended  average 
value  for  materials  such  as  cork,  wood,  asbestos,  brick,  stone,  etc. 
When,  however,  in  the  course  of  compiling  it  was  found  that  each 
material  occurs  in  many  varieties  with  correspondingly  differing  heat 
resistances,  it  was  thought  best  to  tabulate  all  values  conveniently 
available  and  to  let  the  reader  select  the  value  applying  to  his  mate- 
rial. As  explained  in  detail  further  on,  a  close  approximation  to  the 
correct  value  can  be  obtained  from  the  attached  tables  if  care  is 
exercised  to  ascertain  the  important  properties  of  one's  material,  such 
as  density,  moisture  content,  mean  temperature  exposed  to,  and 
perhaps  the  relative  size  of  grains.  If  these  characteristics  are  alike 
in  diflferent  articles,  their  resistance  to  heat  also  will  lie  practically 
alike. 

In  most  of  the  older  textbooks  but  one  value  appears  for  each 
material,  and  since  no  specification  is  given,  and  fabricated  materials 
are  continually  being  changed  in  composition,  old  and  indefinite 
values  are  liable  to  be  misleading.  All  vague  results  are  intended  to 
be  excluded  from  these  tables,  and  the  opinion  is  held  that  such 
values  properly  qualified  as  to  density  and  temperature  are  more 
trustworthy  than  those  identified  merely  by  name 

Reasons  for  Method  of  Classification. 

To  facilitate  the  finding  of  the  heat  conductivity  value  for  any 
material  it  was  first  suggested  to  arrange  the  tables  in  alphabetical 
order.  Since,  however,  many  materials  have  several  designations, 
and  in  many  cases  a  suitable  insulator  is  sought  and  not  a  specific 
product,   it  was  concluded  to  arrange   all  values   in   four   groups  and 


*See  Appendix  for  "Heat  Transmission :     A   National  Research  Council  Project.' 
tRefrigerating  Engineer,  New  York  City. 


HEAT  CONDUCTIVITY  123 

to  enumerate  the  items  approximately  in  the  order  of  their  insulat- 
ing value,  the  material  with  lowest  rate  of  conduction  coming  first. 
Thus,  a  glance  at  a  table  discloses  at  once  the  relative  heat  resist- 
ance of  any  material  listed,  and  over  how  large  a  range  it  extends 
due  to  natural  variations  in  physical  condition  such  as  density  and 
moisture  content.  The  influence  of  temperature  level  is  also  evi- 
dent from  the  tables. 

Another  important  advantage  gained  by  the  group  method  is 
that  a  comparison  can  readily  be  made  of  similar  materials  tested  in 
various  parts  of  the  world.  The  fact  that  the  results  thus  obtained 
with  similar  materials  by  widely  separated  experimenters  are  usually 
in  good  accord,  tends  to  prove  that  the  values  found  are  correct 
and  have  been  verified.  This  knowledge  forms  a  good  basis  for 
estimating  the  heat  insulating  quality  of  some  new  material  which 
may  not  be  listed  in  these  tables 

Results  of  Tests. 

All  the  values  given  are  derived  from  tests.  In  every  instance 
the  authority  for  the  result  given  is  indicated  in  column  10  of  the 
tables 

In  the  past  many  materials  were  tested  in  such  a  way  that  the 
resistance  at  the  surfaces,  that  is  the  temperature  drop  caused  by  the 
inability  of  the  surrounding  air  to  take  up  heat  rapidly  enough,  was 
included  in  the  insulating  power  per  inch  thickness  of  the  material. 
As  explained  in  another  section  of  this  report,  the  proper  basis  for 
comparing  the  heat  insulating  value  of  materials  employed  in  thick- 
nesses exceeding  those  of  gla*s  and  paper  is  their  internal  conduc- 
tivity. Accordingly,  these  are  the  values  included  in  the  attached 
tables,  and  this  explains  why  the  results  of  some  widely  advertised 
tests  could  not  be  included 

Explanation  of  Tables. 

For   simplicity   and   to    prevent   error   in   using    these    tables,   they 
have  been  given  identical  arrangement.     Each   table   has   10  columns, 
numbered. 
I         Column   1   contains  name  and  particulars  of  material  in  question. 

Columns  2  and  3  give  the  density  in  two  ways,  by  specific  gravity 
or  ratio  of  weight  of  material  to  the  weight  of  an  equal  volume  of 
water.  In  other  words,  the  specific  gravity  of  water  is  established  at 
1,  and  its  weight  is  figured  at  62.35  lb.  per  cu.  ft.,  while  in  column 
3  the  apparent  weight  of  the  insulator  as  derived  from  its  bulk,  is 
given  in  lb.  per  cu.  ft. 

Density. 

One  of  the  first  things  to  be  done  in  trying  to  place  insulation 
engineering  on  a  scientific  basis  is  to  emphasize  the  importance  of 
density.  Frequently  it  is  not  advantageous  for  a  manufacturer  to 
discuss   density;    first,   because    it    is   difficult    for    him   to    keep    within 


124  CORK  INSULATION 

a  narrow  limit,  nature's  products  not  always  being  uniform;  second, 
because  moisture  absorption  from  the  atmosphere  may  change  it 
against  his  will,  and  third,  a  rival  may  claim  to  make  an  equivalent 
material  of  a  lower  density,  which,  as  is  well  illustrated  in  Table 
II,  (Mineral  Matter)  would  be  likely  to  yield  a  better  insulating  effect. 
Thus,  in  Table  II  the  heat  conductivity  of  the  heaviest  American 
corkboard  listed  (15.6  per  cu.  ft.)  is  0.3513  B.t.u.  per  hour  against 
0.2693  B.t.u.  for  the  6.9  lb.  variety.  Incidentally,  it  should  be  borne 
in  mind  that  the  structural  strength  of  porous  material  diminishes  as 
its  density  is  lowered. 

A  light  variety  of  corkboard  may  be  a  good  insulator,  and  less 
expensive  to  make  because  it  contains  less  cork  and  more  air,  but 
the  delicate  product  requires  great  care  in  shipping  and  handling,  it 
is  weaker  and,  unless  specially  treated,  it  will  offer  less  resistance  to 
air  and  moisture  penetration.  In  view  of  these  facts,  it  is  customary 
to  employ  for  moulded  cork  pipe  covering  a  quality  of  pure  com- 
pressed cork  varying  in  density  from  20.5  lb.  per  cu.  ft.  ("ice  water 
thickness,"  1-in.  pipe)  to  15.5  lb.  per  cu.  ft.  ("special  thick  brine  cov- 
ering" for  6-in.  pipe)  while  the  weight  of  American  commercial  pure 
corkboard  now  (1923)  varies  from  10  lb.  per  cu.  ft.  in  one-inch 
thick  boards  to  8  lb.  per  cu.  ft.  in  6  in.  thick  slabs. 

Frequently  thin  boards  are  obtained  by  sawing  up  thick  slabs,  and 
so  the  only  way  to  determine  the  true  density  is  to  weigh  the 
boards  used 

These  variations  in  density  involve  of  course  variations  in  con- 
ductivity. 

A  good  example  of  the  value  of  comparison  will  be  found  in 
the  case  of  snow  and  ice,  where  the  values  of  c  found  by  nine  dif- 
ferent experimenters  are  quite  consistent  when  lined  up  in  the  order 
of  density. 

Mean   Test   Temperature. 

Columns  4  and  5  of  the  tables  are  intended  to  state  the  mean 
temperature  of  sample  while  being  tested  for  heat  conductivity. 
The  Centigrade  thermometer  scale  is  preferred  in  testing  labora- 
tories, but  the  Fahrenheit  scale  continues  to  be  used  by  most  Eng- 
lish speaking  engineers,  hence  both  are  given. 

In  the  past  many  investigators  were  not  aware  that  the  mean 
absolute  temperature  has  any  influence  upon  the  heat  conduction  of 
a  material.  When,  in  1908,  Nusselt  extended  his  tests  over  a  wide 
range  of  temperature,  this  fact  became  evident.  For  example,  by 
increasing  the  temperature  of  an  infusorial  earth  block  from  32°  to 
842°  F.  he  found  the  conductivity  to  increase  from  0.51  to  1.02  B.t.u. 
or  to  just  double  the  initial  value.  The  effect  of  absolute  tempera- 
ture is  noticeable  in  all  materials,  but  the  rate  of  change  differs  and 
is  only  very  roughly  proportional  to  the  absolute  mean  temperature 
of  the  sample. 


HEAT  CONDUCTIVITY  125 

It  has  aiso  been  proved  that  the  effectiveness  of  insulators 
depends  upon  their  containing  the  greatest  possible  number  of  minute 
air  cells.  The  solid  portions  or  thin  walls  of  these  air  cells  conduct 
heat  readily,  but  across  the  cells  heat  is  conducted  chiefly  by  radia- 
tion. As  explained  in  another  section  of  this  report,  radiation  in- 
creases with  the  fourth  power  of  the  absolute  temperature  of  the 
heat  exchanging  surfaces,  and  this  explains  why  in  careful  testing 
we  find  that  the  insulating  effect  changes  as  the  mean  working  tem- 
perature is  changed.  The  amount  of  change  varies  with  each 
material. 

Units  of  Heat  Conductivity. 

Columns  6,  7  and  8  express  the  heat  conductivity  in  various  units 
as  defined.  The  physicist  who  prefers  to  work  with  the  Centigrade- 
Gram-Second  system  expresses  his  results  in  gram-calories  of  heat 
passing  in  one  second  through  a  plate  one  centimeter  square,  one 
centimeter  thick,  per  one  degree  C.  difference  in  temperature  of  the 
two  faces  of  plate. 

Using  this  extremely  small  unit  the  conductivity  even  of  silver 
is  equal  to  but  1  gram-calorie.  For  6.9  lb.  corkboard  it  is  0.00009275 
gram-calorie.  In  order  to  eliminate  from  the  tables  at  least  three 
of  the  decimals,  the  true  numbers  in  column  6  are  given  as  they 
appear  after  multiplication  by  1000.  (It  would  be  wrong  to  write 
kilogram   calories   instead.) 

The  results  of  most  European  tests  are  expressed  in  technical, 
metric  system  units,  as  shown  in  column  7.  In  this  case  the  heat 
flow  is  measured  in  kilogram-calories  per  hour  passing  through  a 
plate  of  one  square  meter  area  one  meter  thick,  which  may  be  writ- 
ten as  equivalent  to  1  m'  (1  meter  cube)  per  degree  C.  difference  in 
temperature   between   hot   and   cold  faces. 

Finally  in  column  8  appear  the  values  for  heat  conductivity  in 
technical  English  units,  the  figures  as  given  representing  the  num- 
ber of  British  thermal  units  (B.t.u.)  passing  per  hour  through  a 
plate  of  the  material  one  square  foot  in  area,  one  inch  thick,  and 
per  degree  Fahrenheit  difference  in  temperature  of  the  two  faces. 
These  last  four  words  must  be  added,  otherwise  those  who  care- 
lessly omit  them  invariably  think  it  is  understood  that  the  differ- 
ence between  warm  and  cold  air  each  side  of  board  is  meant.  This 
mistake  is  cleared  up  in  another  section  of  this  report. 

Since  in  refrigerating  plants  heat  must  usually  be  removed 
throughout  24  hours,  it  has  long  been  the  custom  to  use  24  hours 
as  the  time  unit  for  expressing  the  insulating  effect  of  walls,  etc. 
Outside  of  the  laboratory  temperature  conditions  due  to  atmos- 
pheric changes  (sun,  wind,  rain)  are  never  constant  throughout  24 
hours,  and  so  the  committee  has  decided  to  adopt  the  hourly  basis 
for  measuring  heat  flow.  This  also  conforms  with  the  practice  of 
other  than  refrigerating  engineers. 


126  CORK  INSULATION 

In  addition  to  the  three  units  appearing  in  columns  6,  7  and  8, 
a  fourth  one  is  being  advocated  by  physicists.  Their  viewpoint 
is  that  it  is  illogical  when  using  the  foot  (12  in.)  as  the  unit  of  length 
for  determining  areas  to  use  some  other  unit,  the  inch,  for  the 
thickness.  Accordingly,  in  modern  textbooks  such  as  "Mechanical 
Engineers'  Handbook"  by  L.  S.  Marks,  1916,  page  304,  and  in  "Heat 
Transmission  by  Radiation,  Conduction  and  Convection,"  by  R.  Royds, 
1921,  heat  conduction  per  hour  is  based  on  a  piece  one  square  foot 
in  area,  and  one  foot  thick. 

Anyone  preferring  to  calculate  with  this  new  unit  need  only 
divide  the  values  per  inch  thickness  (col.  8)  by  12. 

In  the  metric  system  the  same  unit,  either  the  meter  or  the 
centimeter,  is  used  for  both  area  and  thickness. 

Conversion   Factors   Used. 

For  the  convenience  of  those  accustomed  to  the  use  of  the  units 
employed  in  either  columns  6,  7  or  8,  the  value  appearing  at  the 
original  source  was  translated  into  the  other  units  by  means  of 
the   following  conversion  factors,  using  a  20-inch  slide   rule: 

Value  in  col.  6  X  0.36  =  value  in   col.   7 

Value  in  col.  6  X  2.90291  =  value  in  col.  8 

Value  in  col.  7  -f-  0.36  =  value  in  col.  6 

Value  in  col.  7  X  8.06364  =  value  in  col.  8 

Value  in  col.  8  X  0.344482  =  value  in  col.  6 

Value  in  col.  8  X  0.124013  =  value  in  col.  7 

Column  9  simply  gives  the  reciprocals  of  the  values  in  column  8, 
for  convenience  in  calculations  as  brought  out  in  another  section. 
Thus  the  values  in  column  9  represent  the  heat  resistivity  of  the 
various  materials  enumerated,  that  property  really  being  the  reason 
for  their  use  by  refrigerating  engineers  and  others. 

Column  10  gives  the  source  of  the  information  found  in  the 
preceding  columns.  This  is  quite  useful,  because  it  affords  an  op- 
portunity to  look  up  the  references  given  and  to  satisfy  oneself 
whether  or  not  the  testing  method  used  was  likely  to  give  trust- 
worthy results.  Every  investigator  publishing  his  work  is  convinced 
that  his  results  are  of  a  high  order  of  accuracy,  and  it  is  only  the 
additional  experience  acquired  from  subsequent  investigations  that 
enables  us  to  critically  evaluate  past  accomplishments. 

Results  of  Conduction  Tests. 

The    present    survey   of   the    field    of    heat    conductors    (there   are 
"poor  conductors  of  heat"  but  no  "non-conductors  of  heat")  furnishes 
the  desired  numerical  proof  for  the  existence  of  a  number  of  pecul 
arities  in  insulators. 

In  these  tables  an  attempt  is  made  to  list  the  various  materials 
approximately  in  the  order  of  their  power  to  resist  heat  flow,  the 
best  resistor  coming  first.  This  plan  could  not  be  strictly  adhered 
to,  because  it  was  considered  desirable  for  comparison  to  list  together 


HEAT  CONDUCTIVITY  127 

material  of  the  same  name  but  of  various  densities,  and  to  keep 
together  materials  of  the   same  family,  for  example,  the   corkboards. 

It  will  be  noted  with  surprise  that  some  of  the  loose  insulating 
materials  show  as  low  a  heat  conduction  as  does  air  alone.  This 
is  due  to  the  fact  that  in  a  filled  space  the  diminished  convection  and 
radiation  ofifset  the  conduction  proceeding  through  the  fibers  of  the 
insulator.  The  packing  of  an  air  space  with  insulating  material  is, 
therefore,  of  particular  advantage. 

In  the  absence  of  a  series  of  tests  of  each  material  at  various 
densities,  it  is  hardly  possible  to  state  just  which  density  or  rate 
of  packing  will  result  in  least  heat  conduction.  Randolph,  Table 
III  (Animal  Matter),  obtained  lower  heat  conduction  with  eiderdown 
at  6.8  lb.  per  cu.  ft.  than  he  did  with  4.92  lb.,  because  in  the  latter 
case  there  was  a  better  chance  for  convection.  His  tests  on  absorb- 
ent cotton,  Table  I  (Vegetable  Matter),  lead  to  the  same  conclusion. 
The  heat  conduction  of  dry  granulated  cork  seems  to  depend  more 
upon  the  state  of  division  and  absence  of  foreign  substances  than  on 
the  density,  some  grades  at  3  lb.  per  cu.  ft.  showing  just  as  favorable 
as  grades  three  times  as  dense. 

Comparisons  of  this  kind  should  be  made  at  like  temperature 
levels.  In  Nusselt's  series  of  tests  on  10-lb.  granulated  cork  it  will 
be  observed  that  the  heat  conductivity  increased  from  0.25  B.t.u.  at 
?i2°  F.  to  0.44  at  392°  F.  The  temperature  coefficient,  or  the  increase 
in  c  per  degree  change  from  standard  mean  test  temperature,  such 
as  68°  F.,  is  appreciable  in  all  materials,  but  more  so  in  some  than  in 
others.  All  so-called  insulators  are  more  effective  per  degree  differ- 
ence at  low  than  at  high  temperatures,  that  property  being  due  to 
radiation  in  the  minute  air  cells,  and  due  to  included  moisture,  but  in 
metals  there  is  no  uniform  behavior  in  this  respect,  the  conductivity 
increasing  in  one  metal  and  decreasing  in  another 

Test  Reports  to  Be  Specific. 

It  should  be  evident  from  the  foreging  that  the  heat  conductivity 
of  any  material  is  not  a  fixed  figure.  Honest  investigators  will  not 
fail  to  carefully  describe  the  sample  they  tested  and  to  at  least  give 
its  dimensions,  density  and  range  of  surface  temperatures  used,  other- 
wise their  results  may  not  fit  in  with  correctly  made  tests  and  will 
be  of  no  service  to  discriminating  engineers. 

Temperature   Level  Important. 

Heretofore  there  was  no  universally  recognized  mean  temperature 
of  samples  under  test.  To  obtain  results  within  a  convenient  time  a 
fairly  large  temperature  difference  is  often  resorted  to.  Thus  the 
sample  is  dried  out  much  beyond  its  normal  commercial  state  of  dry- 
ness. Investigators  rarely  report  the  state  of  dryness  after  tests  are 
concluded.  They  aim  to  give  us  a  favorable  looking  value  of  a  bone- 
dry  sample,  kiln-dried  for  weeks  in  some  cases,  when,   in  commercial 


128  CORK  INSULATION 

applications  we  are  interested  in  the  heat  conductivity  of  samples. 
as  received  on  the  job.  The  low  mean  temperature  should  be  used  in 
the  first  test,  and  some  higher  mean  temperature  in  subsequent  tests. 
These  results  should  not  be  averaged  up  into  a  single  value. 

The  successive  drying  out  of  a  sample  is  revealed  by  a  (tempo- 
rary) lowering  of  the  heat  conductivity  as  higher  temperatures  are 
reached;  for  illustration  see  Randolph's  diatomaceous  earth  and 
asbestos  compositions,  20.6  lb.  per  cu.  ft.  At  50°  and  752°  F.  face  tem- 
peratures a  value  of  c  was  obtained  of  0.462  B.t.u.  against  0.718  (55% 
more)  with  50°  and  212°  face  temperatures,  when  in  reality,  with  con- 
stant moisture  content,  the  order  of  these  values  should  be  reversed, 
in  conformity  with  the  results  of  other  investigations. 

To  avoid  drying  out  the  sample  unduly,  the  cold  side  of  the  plate 
is  cooled  by  refrigerated  brine,  at  the  British  National  Physical 
Laboratory  (Table  I,  Vegetable  Matter),  and  in  some  European 
laboratories  by  liquid  air  or  other  cold  fluid. 

Materials  used  in  refrigeration,  and  in  the  construction  of  build- 
ings, should  have  their  normal  rated  heat  conductivity  referred  to  68° 
F.    (20°   C.)   arithmetical  mean  test   temperature. 

While  in  the  tables  columns  4  and  5  are  supposed  to  give  the  true 
mean  test  temperature,  or  else  the  range  used,  this  rule  could  not  be 
adhered  to  in  cases  where  the  original  investigator  neglected  to  spe- 
cifically state  that  the  temperature  given  (if  any)  actually  represents 
the  mean  test  temperature.  It  is  possible  that  some  (as  Norton) 
meant  it  to  be  the  temperature  of  the  hot  face.  Others,  like  Taylor 
and  Griffiths,  gave  both  face  temperatures,  a  method  which  has  much 
in  its  favor.  In  general,  the  data  given  contain  all  that  is  available. 
The  results  of  older  determinations  were  not  obtained  from  the  origi- 
nal sources  stated,  but  were  taken  simply  from  standard  reference 
books,  such  as  the  Smithsonian  Physical  Tables  or  Landolt-Boern- 
stein's  Chemical-Physical  Tables,  1912. 

Moisture  Content. 

As  already  pointed  out,  the  subject  of  moisture  has  not  received 
its  full  share  of  attention  in  the  past.  From  a  few  isolated  tests  and 
observations  in  practice,  and  knowing  that  water  conducts  heat  at 
about  14  times  the  rate  at  which  heat  flows  across  dry  air  cells,  there 
remains  no  doubt  as  to  the  harmful  influence  of  moisture.  Quantita- 
tive measurements,  however,  are  as  yet  incomplete. 

In  Table  1  (Vegetable  Matter),  Biquard  gives  for  French  im- 
pregnated corkboard  weighing  dry  17.17  lb.  per  cu.  ft.,  c  =  0.4195 
B.t.u  per  hr.  After  the  weight  was  increased  by  water  absorption  to 
19.34  lb.,  c  became  0.613  B.t.u.  Here  12.7%  increase  in  weight  caused 
the  conductivity  to  increase  by  49.7%,  equivalent  to  4%  for  each  1% 
gain  in  weight. 

In  Table  I,  near  the  end,  Nusselt  gives  for  Austrian  "cement 
wood,"   dry,  44.6  lb.  per  cu.ft.,   c  =  0.968  B.t.u.     After  moisture   had 


HEAT  CONDUCTIVITY  129 

increased  the  weight  to  51.4  lb.,  c  was  1.21  B.t.u.  Here  15.2%  increase 
in  weight  caused  the  conductivity  to  increase  by  25%,  equivalent  to 
only  1.65%  loss  of  heat  for  each   1%  gain  in  weight. 

In  Table  II  (Mineral  Matter),  Randolph  gives  for  diatomaceous 
earth  and  asbestos  at  20.6  lb.  per  cu.  ft.  a  value  of  c  =  0.57777  B.t.u 
for  a  plain  air-dry  sample,  against  c  =  0.499  when  first  dried  for  three 
days  at  572°  F.  The  ratio  is  1.158  to  1.  Actually  such  a  sample  will 
soon  go  back  to  air-dry  condition,  if  not  worse,  and  then  the  won- 
derfully high  insulating  effect  will  not  longer  obtain. 

A  similar  experiment  is  Nusselt's  who,  as  shown  in  Table  II, 
decreased,  by  roasting,  the  weight  of  fine  river  sand  from  102.4  to 
94.8  lbs.  (excess  8%)  thereby  lowering  c  from  7.825  down  to  2.26 
B.t.u.  The  ratio  of  c  is  as  346%  to  100%  or  43%  heat  loss  for  each 
1%  moisture. 

Under  the  item  masonry.  Table  II,  tests  are  given  of  a  porous 
brick,   showing  the   following   results: 

At  46.1  lb.  (100  %)  c  =  1.17  B.t.u.  (100  %) 
At  49.7  lb.  (107.7%)  c  =  1.695  B.t.u.  (144.8%) 
At   58.8   lb.    (127.5%)    c   =   2.743    B.t.u.    (234.2%) 

It  will  be  noted  that  for  each  1%  increase  in  weight,  c  increased 
5.82'/    in  the  second  test  and  4.88%,  on  the  average,  in  the  third  test. 

In  the  case  of  the  machine  made  brick  weighing  101.1  lb.  per 
cu.  ft.  the  addition  of  moisture  increased  c  from  3.34  up  to  6.64  B.t.u. 
per  hour. 

Further  tests  are  necessary  before  the  influence  of  moisture  can 
be  expressed  by  a  correct  formula,  but  for  the  time  being  it  may  be 
assumed  that  each  1%  gain  in  weight  by  moisture  absorption  causes 
the  heat  conductivity  of  previously  dry  slabs  and  bricks  to  increase 
by  about  5%.  Thus  20%  addition  in  weight  is  likely  to  double  the 
original  conductivity.  Cork  and  other  pipe  coverings  long  in  use 
afford  a  good  chance  for  checking  this  estimate. 

If  we  figure  that  the  British  slag  wool.  Table  II  (Mineral  Mat- 
ter), originally  had  a  value  of  c  =  0.29,  as  is  probable,  then  its  value 
of  c  =  0.35,  after  14  years  use,  represents  a  loss  of  0.006  B.t.u..  or 
20.7%.  This  change  in  insulating  effect  is  caused  by  moisture.  I^osses 
up  to  this  magnitude  must  be  expected  whenever  corkboard  is  incor- 
porated in  forms  exposed  to  wet  concrete.  Hence  this  practice  is 
to  be  discouraged. 

Observations  of  this  kind  from  actual  practice  are  of  greater 
value  to  refrigerating  engineers  than  are  tests  of  kiln  dried  samples. 

Tables  I  to  IV  (Vegetable  Matter,  Mineral  Matter,  Animal  Mat- 
ter and  Metals)  contain  no  test  results  on  air  spaces  and  surface 
resistance.  Reliable  data  on  these  items  have  appeared  but  recently, 
but  it  is  intended  to  compile  this  information  and  to  include  it  in  a 
future  report. 


130 


CORK  INSULATION 


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166  CORK  INSULATION 

Section  XI  of  *'Heat  Transmission  of  Insulating  Ma- 
terials," published  by  the  American  Society  of  Refrigerating 
Engineers,  New  York  City,  is  a  Bibliography  of  "References 
to  articles  and  publications  treating  of  heat  insulation  and 
heat  transfer,"  compiled  by  Chas.  H.  Herter,  with  the  cooper- 
ation of  A.  J.  Wood  and  E.  F,  Grundhofer  of  the  Pennsylvania 
State  College.  The  source  and  year  of  publication,  name  of 
author  and  title  are  given  in  practically  all  listings. 

Space  does  not  permit  the  appending  of  this  Bibliography, 
although  its  value  in  connection  with  the  foregoing  tables  of 
thermal  conductivity  of  various  insulating  materials  will  war- 
rant its  possession. 


CORK    INSULATION 


Part  III — The  Insulation  of  Ice  and  Cold  Storage 
Plants  and  Cold  Rooms  In  General. 


CHAPTER  XI. 

REQUIREMENTS     OF    A     SATISFACTORY     INSULA- 
TION FOR  COLD   STORAGE  TEMPERATURES. 

80. — Essential  Requirements. — The  widening  knowledge  of 
the  use  of  refrigeration  created  a  very  definite  demand  for 
a  suitable  insulation  for  cold  storage  temperatures,  which 
resulted  in  the  introduction  in  1893  of  pure,  compressed,  baked 
corkboard,  the  superior  qualities  of  which  were  apparent 
almost  from  the  beginning;  and  its  application  became  so 
general  during  the  first  quarter  century  of  its  use  as  to  prac- 
tically displace  all  competing  materials,  and  strictly  on  its 
merits  alone  has  become  the  accepted  standard  insulation  for 
cold  storage  temperatures  wherever  refrigeration  is  employed. 

It  is  by  no  mere  chance,  of  course,  that  cork  bark  is  the 
foundation  for  the  one  satisfactory  insulating  material  for 
cold  storage  temperatures ;  and  the  reason  for  its  universal 
acceptance  and  extensive  use  is  easily,  though  not  generally, 
understood. 

Pure  corkboard,  as  an  ideal  insulating  material  for  cold 
storage  temperatures,  excels  in  every  single  particular;  but 
it  possesses  one  inherent  quality  without  which  it  could  not 
have  been  used  for  cold  storage  work  at  all — it  is  inherently 
nonabsorbent  of  moisture,  that  is,  does  not  possess  capillarity,  the 
property  that  causes  a  blotter  to  suck  up  ink ;  for  cold  storage 
temperatures  very  definitely  involve  moisture  conditions, 
through  the  medium  of  the  condensation  of  water  against  cold 
surfaces,  and  any  material  that  is  to  retain  its  initial  insulat- 
ing efficiency  in  the  almost  continuous  presence  of  moisture, 
must  be  impervious  to  moisture,  must  be  inherently  free  from 
167 


168  CORK  INSULATION 

capillarity,  else  it  will  become  saturated  with  water  and  lose 
its   insulating  worth   entirely. 

A  satisfactory  insulation  for  any  purpose  whatever  must 
be  able  to  retard  the  flow  of  heat  to  an  unusual  degree.  Many 
materials  will  do  this,  but  a  satisfactory  insulation  for  cold 
storage  temperatures  must  combine  with  such  insulating 
property  the  ability  to  retain  its  insulating  efificiency  for  an 
indefinite  period  under  the  adverse  conditions  of  the  constant 
presence  of  moisture.  Pure  corkboard  meets  this  very  exact- 
ing combination  of  these  two  major  requirements  to  a  degree 
never  yet  approximated  under  actual  operating  conditions  by 
any  other  insulation. 

Then,  too,  the  delicacy  of  many  foodstuffs  makes  them 
peculiarly  susceptible  to  tainting,  and  the  insulation  must 
keep  free  from  rot,  mold  and  offensive  odors,  and  be  germ- 
and  vermin-proof;  economical  building  construction  requires 
an  insulation  that  possesses  ample  structural  strength  and  in 
such  form  that  it  can  be  installed  easily  in  all  types  of  build- 
ings ;  conservation  of  valuable  space  requires  an  insulation 
that  is  compact  and  occupies  minimum  space;  the  reduction 
of  fire  hazard  calls  for  an  insulation  that  is  '^low-burning  and 
fire-retarding;  and  in  the  interests  of  economy,  the  insulating 
material  must  be  easily  obtained  and  reasonable  in  cost.  Pure 
corkboard  also  meets  these  secondary  but  nevertheless  impor- 
tant requirements  better  than  any  other  insulating  material 
that  has  ever  been  offered  commercially. 

81. — A  Good  Nonconductor  of  Heat. — It  has  been  seen  that 
heat  transference  is  accomplished  by  conduction,  convection 
and  radiation ;  and  that  when  the  problem  of  insulating  a  cold 
room,  for  example,  is  under  consideration,  the  heat  transfer 
by  conduction  is  the  most  important,  consisting  of  ninety  per 
cent  or  more  of  the  total  heat  leakage  into  the  room  when  a 
suitable  insulating  material  is  employed. 

It  will  be  recalled  that  the  heat  conductivity  of  dense  sub- 
stances, such  as  metal,  is  high  ;  that  of  lighter  materials,  such 
as  wood,  is  less ;  while  that  of  gases  is  very  low.  Thus  air, 
the  most  available  gas,  is  the  poorest  conductor  of  heat,  if  a 
vacuum  is  excepted,  but  air  is  a  good  convector  of  heat,  unless 


I 


REQUIREMENTS  OF  AN  INSULATION  169 

it  is  broken  up  into  great  numbers  of  minute  particles,  so  small 
in  size  that  the  effect  of  convection  currents  is  reduced  to  a 
negligible  quantit}'. 

Consequently,  in  an  efficient  insulating  material,  air  must 
be  present  in  the  very  smallest  possible  units,  such  as  atoms, 
so  that  convection  is  reduced  to  a  minimum ;  and  since  these 
atoms  of  air  must  each  be  confined,  the  use  of  a  very  light 
encompassing  material  having  little  density  and  thus  very  Iom^ 
conduction,  is  essential.  Such  an  insulator  will  be  as  efficient 
from  the  standpoint  of  heat  transfer  as  it  is  possible  to  obtain ; 


FIG.    47.— CORKBOARD    UNDER    POWERFUL    MICROSCOPE,    SHOWING 
CONCEALED  AIR  CELLS. 

'  that  is,  a  very  light  material  containing  myriads  of  micro- 
scopic air  cells,  each  one  sealed  unto  itself. 

The  outer  bark  of  the  cork  oak  was  evidently  provided  by 
nature   to   prevent  the   sun's  rays   and   the   hot   winds   from 

\  drying  up  the  life-sustaining  sap  that  courses  through  the 
inner  bark  of  this  peculiar  and  remarkable  tree ;  and  an  exam- 
ination under  the  microscope  reveals  the  reason  why  cork  is 
such  an  excellent  nonconductor  of  heat.  It  is  found  to  be 
composed  of  countless  air  cells,  so  tiny  and  infinitesimal  that 
it  takes  many  millions  of  them  to  fill  a  cubic  inch  of  space. 
Flow  of  heat  bv  convection  is  therefore  reduced  to  the  lowest 


170 


CORK  INSULATION 


conceivable  minimum,  because  the  velocity  that  can  be  ob- 
tained by  air  in  so  small  a  space  is  virtually  nil.  Again,  these 
cells  are  separated  from  each  other  by  thin  v^^alls  of  tissue  of 
very  low  density.  Thus  the  flow  of  heat  by  conduction  is  as 
low  as  is  reasonable  to  expect  in  any  material  extant. 


FIG.    48.— r.OILlNG    TEST    ON    CORKBOARD    INSULATION. 

It  would  therefore  l)e  but  natural  to  find  this  outer  bark 
an  excellent  nonconductor  of  heat,  and  the  experience  of 
many  years  with  pure  corkboard  has  amply  confirmed  this 
deduction. 


82. — Inherently  Nonabsorbent  of  Moisture.  —  A  satisfac- 
tory insulation,  however,  for  any  purpose,  must  retain  its 
insulating  efficiency  indefinitely.     That  is,  it  must  not  pack 


REQUIREMENTS  OF  AN  INSULATION  171 

down  and  lose  its  original  "dead-air"  content ;  and  it  must 
not  become  saturated  with  moisture,  since  water  is  a  rela- 
tively good  conveyor  of  heat.  Suitable  materials  for  the  insu- 
lation of  warm  or  hot  surfaces  may  possess  the  property  of 
absorbing  water,  for  under  normal  conditions  of  service  they 
are  rarely  subjected  to  severe  moisture  conditions  and  are 
almost  constantly  undergoing  a  drying  out  process;  but  cold 
storage  temperatures,  on  the  other  hand,  involve  moisture 
conditions,  through  the  precipitation  of  moisture  from  air  in 
contact  with  cold  surfaces,  and  any  material  that  is  to  retain 
its  original  insulating  efficiency  in  the  almost  continuous  pres- 
ence of  moisture  and  in  the  absence  of  appreciable  heat,  must 
be  impervious  to  moisture.  In  a  word,  a  satisfactory  insula- 
tion for  cold  storage  temperatures  must  be  inherently  free 
from  capillarity,  as  otherwise  it  will,  in  the  presence  of  moist- 
ure, become  saturated  and  of  no  further  value  as  an  insulating 
material. 

At  least  as  early  as  the  reign  of  Augustus  Caesar,  cork  was 
used  as  stoppers  for  wine  vessels,  and  has  been  used  during 
the  intervening  2,000  years,  practically  unchallenged,  as  stop- 
pers for  liquid  containers,  thus  amply  demonstrating  its  inher- 
ent imperviousness  to  moisture.  And  this  important  property 
of  cork — its  entire  freedom  from  capillarity — is  in  no  way 
impaired  by  the  manufacturing  process  follow'ed  in  the  pro- 
duction of  pure  corkboard.  On  the  contrary,  the  inherent  or 
natural  ciualities  of  cork  that  makes  it  the  basis  for  the  best 
cold  storage  insulation  yet  discovered  or  developed  on  a 
commercial  scale,  are  enhanced  by  the  baking  of  the  granules 
of  pure  cork  bark  in  metal  molds  under  pressure  at  moderate 
temperature ;  for  such  manufacturing  process  brings  out  the 
natural  resin  of  the  cork,  which  cements  the  particles  firmly 
together  and  makes  the  use  of  an  artificial  binder  unnecessary, 
and  by  coating  the  entire  surface  of  each  separate  granule 
with  a  thin  film  of  the  natural  waterproof  gum  affords  an 
additional  barrier  against  the  possible  entrance  of  moisture. 

The  "Navy  Test"  was  designed  by  the  United  States  Navy 
Department  some  years  ago  to  concentrate  in  a  short  period 
of  time  those  destructive  forces  to  which  all  cold  storage 
insulation  is  subject  during  its  term  of  actual  service.     The 


172  CORK  INSULATION 

test  consists  of  boiling  a  piece  of  insulation  completely  sub- 
merged for  three  hours  at  atmospheric  pressure  without  its 
disintegrating  and  without  its  expanding  more  than  two  per 
cent  in  any  direction.  Pure  corkboard  of  standard  quality 
easily  meets  the  requirements  of  this  test,  merely  demonstrat- 
ing in  a  simple  laboratory  way  that  corkboard  insulation  is 
proof  against  deterioration  in  service  from  the  destructive 
action  of  moisture  that  is  ever  present  at  cold  storage  tem- 
peratures. 

83. — Sanitary  and  Odorless. — Any  insulating  material  em- 
ployed at  cold  storage  temperatures  usually  encounters 
foodstuffs,  and  should  therefore  be  perfectly  sanitary  and 
free  from  mold,  rot,  appreciable  odor  or  vermin.  For  these 
reasons  any  insulation  in  which  binders  are  used,  especially 
pitch,  is  dangerous,  since  the  delicacy  of  many  foodstuffs 
makes  them  peculiarly  susceptible  to  tainting  and  contamina- 
tion. 

Pure  corkboard  contains  no  foreign  binder  of  any  charac- 
ter and  the  cork  bark  of  which  it  is  composed  is  inherently 
moisture-proof.  Therefore  it  will  not  rot,  mold  or  give  off 
offensive  odors ;  and  if  corkboard  is  properly  erected,  it  is 
vermin-proof.  Cold  storage  rooms  insulated  with  pure  cork- 
board, and  finished  with  Portland  cement  troweled  smooth,  as 
recommended  by  the  United  States  Department  of  Meat  In- 
spection, are  easily  and  indefinitely  kept  in  sanitary  and  hy- 
gienic condition  by  ordinary  washing  and  cleansing  methods. 
The  sanitary  and  odorless  qualities  of  an  insulation  for  cold 
storage  temperatures  are  of  very  real  importance,  and  pure 
corkboard  is  easily  the  standard  by  which  all  cold  storage 
insulating  materials  are  judged. 

84. — Compact  and  Structurally  Strong. — It  has  been  noted 
that  a  particle  of  cork  bark  is  made  up  of  a  myriad  of  tiny 
sealed  air  cells,  separated  from  each  other  by  thin  walls  of 
tissue  of  very  low  density,  each  cell  containing  a  microscopic 
bit  of  air.  In  the  manufacture  of  pure  corkboard.  of  standard 
specifications,  the  particles  of  cork  bark  are  sufficiently  com- 
pressed  in   the   molds    to    eliminate    the    voids   between    the 


REQUIREMENTS  OF  AN  INSULATION 


173 


particles,   which   produces   a   finished   material   of   maximum 
compactness  in  relation  to  weight  and  insulating  value. 

This  compactness  is  an  essential  quality  of  pure  corkboard, 
a  quality  not  possessed  in  proportionate  degree  by  other  insu- 
lating materials.  In  fibrous  materials,  or  materials  not  of 
cellular  structure,  the  insulating  value  is  dependent  on  air 
spaces,  which  are  not  independent  of  each  other.  The  air 
content  is  merely  entrapped  between  closely  matted  or  inter- 
laced fibres,  such  interstices  or  voids  being  connected  one 
with  another ;  and  when  moisture  contacts  with  such  materials 


[G.    49.— PURE    CORKBOARD    INSULATION    IN    MODERN    FIBRE    CARTON 
CONTAINING   12   BOARD    FEET. 

I  it  is  readily  communicated,  not  alone  by  capillarity  but  also 

iby  gravity,  from  one  air  space  to  another. 

The  inherent  ruggedness  and  toughness  of  cork  bark  is 
one  of  its  outstanding  and  well-known  qualities;  and  after  it 
has  been  properly  processed  into  sheets  of  pure  corkboard,  the 
resultant  product  is  sufficiently  strong  to  permit  of  its  being 
transported,  handled  and  used  as  readily  as  lumber,  its 
strength  in  compression  being  sufficient  to  take  care  of  loads 
many  times  greater  than  ordinarily  encountered.  The  remark- 
able strength  of  such  an  excellent  nonconducting  material  is 
simply  another  of  the  very  important  reasons  for  its  universal 
use  for  all  cold  storage  purposes. 


174  CORK  INSULATION 

85. — Convenient  in  Form  and  Easy  to  Install. — The  stand- 
ard sheet  of  pure  corkboard,  12  inches  wide  and  36  inches 
long",  which  all  American  and  most  foreign  manufacturers 
follow  as  a  standard,  is  the  most  convenient  in  form  for  every 
purpose.  It  may  be  handled,  sawed,  and  applied  as  readily 
as  lumber,  or  put  up  in  Portland  cement  or  hot  asphalt  cement 
with  the  same  ease  as  any  common  building  material.  Its 
characteristics  are  such  that  there  need  be  little,  if  any,  waste 
from  sawing  and  fitting-,  because  the  fractional  sheets  may  be 
neatly  and  tightly  assembled  to  give  as  efificient  an  installation 
as  could  be  had  with  the  full  size  standard  sheets. 


FIG.    50.— APPARATUS    FOR    SIMPLE    FIRE    TEST    ON    PURE    CORKBOARD. 

86. — A.  Fire  Retardant. — In  the  manufacture  of  pure  cork- 
board,  partial  carbonization  of  the  raw  cork  bark  is  accom- 
plished without  destruction  of  tissue,  that  is,  the  baking  proc- 
ess, at  moderate  temperatures,  dissolves  the  resins  (inherent 
in  cork  bark)  sufficiently  to  everlastingly  bind  the  particles 
into  a  good,  strong  sheet  of  insulation,  while  at  the  same  time 
producing  a  protection  of  carbon  that  a  flame  penetrates  with 
much  difficulty. 

A  simple  experiment  to  show  the  slow-burning  and  fire- 
retarding  properties  of  pure  corkboard  as  compared  with  other 
materials  can  be  made  by  anyone  by  means  of  an  iron  rack 
and  a  gas  burner.  Place  the  sample  of  insulation  on  the  rack 
and  record  the  time  it  takes  to  burn  a  hole  clear  through  and 


-  1 

i 


REQUIREMENTS  OF  AN  INSULATION 


175 


carefully  note  the  condition  of  each  sample  at  the  conclusion 
of  each  test.  A  piece  of  pure  corkboard  two  inches  thick  will 
not  burn  through  under  about  four  hours  if  subjected  in  this 
way  to  a  1500°  F.  gas  flame;  and  when  this  is  compared  with 
the  condition  of  other  kinds  of  cold  storage  insulating  mate- 
rials at  the  end  of  similar  tests,  it  will  be  clear  why  the  under- 
writers have  given  their  approval  to  pure  corkboard  and  to  no 
other  form  of  cold  storage  insulation. 


•     PIG.     51.— CORKBOARD    INSULATION     ON     BRICK     WALL— APPROVED    BY 
NATIONAL   BOARD    OF   UNDERWRITERS. 


Many  examples  of  the  remarkable  value  of  pure  corkboard 
as  a  fire  retardant  could  be  selected  from  the  fire  records  of 
the  past  thirty  years  or  so,  if  it  were  any  longer  necessary 
in  the  minds  of  insulation  users  to  offer  proof  of  this  well- 
known  fact ;  but  possibly  it  will  serve  a  double  purpose  to 
make  specific  mention  here  of  a  fire  that  lasted  nine  hours  in 
the  grocery  of  A.  Weber  of  Kansas  City,  Missouri,  on  Decem- 
ber 3,  1914,  and  which  consumed  e\'erything  of  value  in  the 


176 


CORK  INSULATION 


basement  except  the  corkboard  insulated  cold  storage  room. 
Fifty  hours  after  the  fire  started  the  frost  still  remained  on 
the  pipes  in  this  room,  which  was  then  found  to  be  only  38°  F., 
a  rise  in  temperature  of  but  10°  from  the  time  the  fire  started. 
Thus  not  only  the  fire  retarding  property  of  pure  corkboard 
was  spectacularly  demonstrated, — the  Portland  cement  finish 
having  been  destroyed  but  the  corkboard  having  escaped 
almost  unharmed, — but  the  remarkable  insulating  value  of 
pure  corkboard  was  most  effectivel}-  demonstrated  as  well. 


FIG.  52.— BASEMENT  OF  WEBER'S  STORE  AFTER  THE   FIRE.— NOTE 
CORKBOARD  WALLS  OF  THE  COLD  STORAGE  ROOM  IN  BACKGROUND. 


Other  demonstrationsf  of  what  pure  corkboard  will  do  in 
actual  fires  have  been  so  numerous  as  to  attract  considerable 
attention.  In  cold  storage  plants  in  particular,  total  destruc- 
tion of  buildings  and  equipment  has  often  been  prevented 
solely  by  the  corkboard  walls  of  the  cold  storage  rooms. 

87. — Easily  Obtained  and  Reasonable  in  Cost. — Pure  cork- 
board can  today  be  classed  as  merchandise,  and  is  carried  in 
stock  in  every  city  of  any  importance  in  the  United  States.  In 
addition,  large  supplies  are  always  on  hand  in  storage  ware- 
houses at  New  York  and  New  Orleans,  and  at  the  four  facto- 


tSee  Appendix  for  "How  Insulation  Saved  a  Refinery.' 


REQUIREMENTS  OF  AN  INSULATION  177 

ries  that  manufacture  corklDoard  in  the  United  States.  Con- 
sequently, pure  corkboard  insulation  is  almost  as  easily  ob- 
tained in  this  country  as  is  any  approved  building  material 
in  common  use ;  and  considering  its  permanent  insulating 
worth  and  general  utility,  is  fairly  priced  and  often  to  be  had 
at  a-  cost  that  makes  its  purchase  an  unusually  attractive 
investment. 

88. — Permanent  Insulating  Efficiency.— Thus  it  will  be 
noted  that  the  requirements  of  a  satisfactory  insulation  for 
cold  storage  temperatures  cover  a  wide  range  indeed,  and 
may  be  summed  up  briefly  in  the  statement  that  such  insula- 
tion must  be  of  such  permanent  thermal  resistivity,  obtainable 
in  such  form,  structurally  suitable  in  such  degree,  readily 
available  in  such  quantity  and  at  such  price,  as  to  make  tliat 
insulating  material  one  of  permanent  insulating  worth  and 
efficiency. 

There  are,  perhaps,  a  numl^er  of  insulating  materials  of 
various  kinds  and  in  various  forms,  that  show,  under  labora- 
tory tests,  when  such  materials  are  new  and  dry  and  unused, 
a  heat  resistivity,  or  an  insulating  value,  as  high  as,  or  higher 
than,  pure  corkboard  insulation  ;  but  for  many  years  it  has 
been  the  actual  experience  of  countless  insulation  users  that 
pure  corkboard  of  proper  thickness  applied  in  the  proper 
manner  is  the  only  cold  storage  insulation  for  which,  from 
every  consideration,  permanent  efficiency  can  be  claimed. 


CHAPTER  XII. 

PROPER  THICKNESS   OF   CORKBOARD   TO   USE 
AND   STRUCTURAL  SUGGESTIONS. 

89. — Economic  Value  of  Insulating  Materials. — During  the 
past  fifteen  years  or  so  there  has  been  considerable  time  and 
attention  given  to  the  study  of  insulating  materials,  both 
theoretical  and  practical ;  but  the  results  have  taken  the  form 
of  the  determination  and  comparison  of  the  thermal  efficiency 
of  many  materials,  and  the  best  methods  of  erecting  and 
caring  for  them  in  service,  rather  than  having  dealt  with  the 
determination  of  the  range  of  profitable  expenditure  which  is 
the  real  aim  and  end  of  industrial  research.  In  the  absence 
of  any  concrete  information  of  generally  recognized  worth  on 
the  subject  of  how  much  money  it  is  advantageous  to  expend 
for  cold  storage  insulation,  the  users  of  such  materials  have 
divided  into  two  main  classes :  First,  those  who  came  to 
believe  that  it  was  not  profitable  to  employ  as  much  insula- 
tion as  generally  recommended  by  responsible  manufacturers, 
or  who  came  to  believe  that  cheaper  materials  in  the  same 
thicknesses  would  suffice ;  and,  secondly,  those  whose  experi- 
ence and  judgment  taught  them  that  increased  thicknesses  of 
only  the  best  insulating  materials  were  profitable  to  install. 

Those  in  the  first  class  are  much  in  the  minority,  yet 
their  numbers  justify  careful  consideration  of  their  policy. 
It  might  be  expected  that  a  third  class  exists,  consisting  of 
those  who  have  not  changed  their  insulation  ideas  and  prac- 
tices during  the  period  of  time  mentioned ;  but  it  is  believed 
that  these  are  now  so  few  in  actual  numbers  as  to  be  of  no 
real  importance  with  respect  to  a  discussion  of  this  subject. 

The  true  economic  value  of  an  insulating  material  must,  of 
course,    follow   rather   closely   a   consideration   of   the   monetary 

178 


STRUCTURAL  SUGGESTIONS 


179 


return  on  the  initial  insulation  investment  for  the  period  of 
the  useful  expectancy  of  such  insulation.  The  factors  to 
which  it  is  possible  to  assign  definite  values  are : 

(a)  Value  of  heat  loss  through  insulation  in  terms  of  total  cost  to 
remove  it. 

(b)  Interest  on  the  insulation  investment. 

(c)  Insurance  on  the  insulation  investment. 

(d)  Cost  of  insulation  repairs  and  depreciation. 

(e)  Value  of  building  space  occupied  by  insulation. 

In  addition,  there  are  certain  factors  for  or  against  more  and/or 
better  insulation,  the  value  of  which  it  is  often  difficult  to 
determine  or  predict,  as  follows: 

(f)  Term  of  useful   expectancy   for   insulation,   or  probable   obso- 
lescence period. 

(g)  Improvement  in   product  from  better  temperature  conditions 
due  to  insulation. 

(h)   Advertising  value  of  better  cold  storage  equipment, 
(i)     Saving  in  cost  of  bringing  product  and/or  room  to  tempera- 
ture, 
(j)    Saving   resulting   from   ability    to    anticipate   with   reasonable 

accuracy  the   drop   in   thermal   efficiency   of   the   insulation   in 

service, 
(k)   Type  and  character  of  structure  to  which  insulation  is  to  be 

applied. 
(1)    Ability  to  obtain  proper  application  of  insulation, 
(m)  Effect    of   type,    temperature    and    continuity   of    refrigeration 

applied, 
(n)   Effect  of  outside  atmospheric  conditions, 
(o)   Effect  of  air  humidity  maintained  in  insulated  rooms, 
(p)   Effect  of  the  arrangement  of  product  stored  and  its  influence 

on  air  circulation  over  insulation. 
(q)   Effect  of  anticipated  abuse  of  insulation  and  failure  to  make 

repairs, 
(r)   Funds  available. 

Mr.  P.  Nicholls*,  Pittsburgh,  Pa.,  working  along  these 
lines  and  taking  the  general  case  of  a  flat  surface  with  insula- 
tion applied  to  it,  developed  the  formula : 


=  1.74>/. 


0.327P 


A(T:,— t)   F  + 


K( 


lUO 


R'  + 


(T.n-t) 

-^  xc 


+  8.3S 


in  which 

X  =  economic  thickness  of  insulation  in  inches,  that  is,  the  tbick- 


*P.    Nicholls,    Supervising   Engineer,    Fuel   Section,    Bureau   of   Mines   Experiment 
Station,   U.    S.    Dept.    of   Commerce,    Pittsburgh,   Pa. 


ISO  CORK  INSULATION 


i 


ness  that  will  reduce  to  a  minimum  the  sum  of  the  expenses 
due  to  the  heat  leakage  through  the  insulation  plus  the  ex- 
penses of  preventing  the  additional  heat  leakage. 

C  =  average  thermal  conductivity  coefficient  of  insulation  during 
its  life,  in  B.t.u.  per  square  foot,  per  inch  thickness,  per  hour, 
per  degree  temperature  difference  F. 

B  =  cost  of  insulation  installed,  in   dollars  per  square  foot,  per 
inch    thickness,    or    in    dollars    per    board    foot.      (Note: 
H 

B  =  ( h  B')    where    H  =  the    fixed    square    foot    cost    to 

X 
cover  wall   finish,   plaster,   starting  the   insulation  job,   etc., 
and  B'  =  cost  of  insulation  per  square  foot  that  is  propor- 
tional to  the  thickness.) 
I  =  per  cent  interest  allowed  on  insulation  investment,  plus  per 
cent  insurance  cost. 

Y  =  years  of  life  allowed  insulation. 

R  =  yearly  repair  cost,  as  per  cent  of  investment  in  insulation. 

F  =  fraction  of  year  room  is  in  operation. 
Tm  =  maximum   temperature  during  the   period   of  yearly   opera- 
tion of  the  outside  air  adjacent  to  cold  storage  room  wall, 
in  degrees  F. 
t  =  cold  room  temperature,  in  degrees  F. 

tp  :=  mean  temperature  of  cooling  coil  piping. 

K  =:  surface  transmission  coefficient  of  pipe  surface  in  B.t.u.,  per 
square  foot,  per  hour,  per  degree  F. 

A  =  average  cost  over  period  of  yearly  operation,  in  dollars,  of 
one  ton  of  refrigeration  (cost  per  B.t.u.  X  288,000)  delivered 
to  the  room  under  consideration,  exclusive  of  cooling  piping. 

P  =  cost  in  dollars  of  the  pipe  per  square  foot  of  its  surface, 
including  installation  and  accessories. 

G  =  investment  in  refrigerating  equipment,  of  whatever  nature, 
in  dollars  per  ton  of  refrigeration  per  day.  This  excludes 
machinery,  the  cost  burden  of  which  is  included  in  A. 

288,000  P  I 

(Note:     G  = )  1 

24  K  (tp— t) 

P  =:  per  cent  interest  allowed  on  refrigerating  equipment  invest- 
ment covered  by  G. 

Y'  =  years  of  life  allowed  refrigerating  equipment  covered  by  G. 

R'  =  yearly  repair  cost,  as  per  cent  of  investment  in  refrigerat- 
ing equipment  covered  by  G. 

S  =  yearly  value  of  one  cubic  foot  of  space  occupied  by  insula- 
tion. 

U  =  the  over-all  thermal  coefficient  of  heat  transmission  from  air 
to  air  for  the  given  thickness  of  the  entire  wall,  other  than 
insulation,  and  including  the  surface  transmission  coefficients 
of  the  outside  wall  surface  and  the  inside  insulated  wall 
surface. 

By  substituting: 

C  =  0.35  B.t.u. 

ro.o4 

B  =  ^ 1-0.16   (^dollars 


I  r=  6  per  cent. 
Y  =  15  years. 
R  =  3  per  cent. 
F  =  1  year. 


STRUCTURAL  SUGGESTIONS 


181 


T»  =  50°  F.  average  temperature  outside  wall. 

Tm=r90°    F. 

t  =  cold  room  temperature,  degrees  F.,  as  assigned, 
(t— tp)  =  10°  F. 

K  =  2.0  surface  transmission  coefficient. 
A  =  $1.00  per  ton. 
P  z=  $4.35  per  square  foot. 
I'  =  6  per  cent. 
Y'  =  8  years. 
R'  =  3  per  cent. 
S  =  0. 
U  =  0.303. 

the  economical  thickness,  X,  of  insulation  was  readily  obtained 

for  a  range  of  cold  room  temperatures,  t,  and  curve  B  of  Fig. 

53  was  platted. 


\ 

\  eo      -lo 

I    I 


±s±. 


FIG.    53.— WALL  INSULATION— ECONOMIC   THICKNESS   AGAINST 
TEMPERATURE. 

With  the  same  set  of  conditions  and  a  cold  room  tempera- 
ture of  20°  F.,  the  true  yearly  cost,  per  square  foot,  based  on 
various  thicknesses  of  insulation,  were  computed  and  curve  B 
of  Fig.  54  was  platted. 

According  to  the  definition,  the  economic  thickness  of 
insulation  occurs  when  the  yearly  cost  is  a  minimum,  which 
thickness  is  (3.99 — 1.06)  2.93  inches  on  the  curve  in  Fig.  54; 
and  the  shape  of  the  curve  shows  that  the  refrigeration  cost 
per  square  foot  increases  at  a  more  rapid  rate  with  a  given  de- 
crease below  the  economic  thickness  than  it  does  for  a  similar 
increase.  It  will  also  be  noted  that  such  curve  is  compara- 
tively flat  on  each  side  of  the  economic  thickness,  indicating 


182 


CORK  INSULATION 


that  a  small  change  in  insulation  thickness,  either  above  or  be- 
lozv  the  true  point  of  maximum  economy,  zvill  not  materially 
affect  the  cost  of  refrigeration  per  square  foot. 

The  real  value  of  the  work  of  Mr.  Nicholls  is  summarized 
in  the  two  deductions  just  set  forth  in  italics,  rather  than  in 
the  numerical  results  obtained  for  economic  thicknesses  of 
insulation  as  shown  by  the  curves,  because  values  for  factors 
(f)  to  (r)  could  not  be  assigned  and  made  a  part  of  the 
formula. 


V 

i 

\y 

- 

1 

u 

-• 

\^ 

f 

^ 

1 

; 

k 

-^ 

% 

1 

f 

a/0 

n 

B:i 

iqomi 

■  J 

%i 

' 

\ 

1 

^< 

7 

/             A 

w 

L* 

3 

'        <5 

f        £ 

}        /O 

^  Vl 


FIG.  54.— YEARLY  WALL  COST  PER  SQUARE  FOOT  AGAINST  THICKNESS 
OF  INSULATION. 


90. — Tendency  Toward  More  and  Better  Insulation. — Many 
years  ago  a  responsible  manufacturer  of  pure  corkboard* 
pointed  out  that : 

The  proper  thickness  of  .  .  .  corkboard  to  install,  in  order  to 
maintain  a  given  temperature  economically,  depends,  as  with  every 
other  type  of  insulation,  upon  several  factors,  which  vary  in  the  case 
of  each  plant: 

(a)  The  character  of  the  building — whether  brick,  stone,  concrete, 
hollow  tile  or  frame; 

(b)  The  thickness  of  the  walls,  floors  and  ceilings* 

(c)  The  temperature  to  be  maintained; 

(d)  The  climatic  conditions; 

(e)  The  character  of  the  material  to  be  stored  or  the  purpose  for 
which  the  rooms  are  to  be  used; 

(f)  The  cost  of  producing  refrigeration. 


*Armstrong   Cork   Company,   Insulation   Department,   Pittsburgh,    Pa. 


STRUCTURAL  SUGGESTIONS  183 

Each  case  that  arises  must  be  considered  on  its  own  merits.  Gen- 
erally speaking,  however,  it  may  be  said  that  under  average  condi- 
tions, the  thicknesses  of  .  .  .  corkboard  that  can  be  economically 
installed  for  the  several  temperatures  noted,  are  as  follows: 

ORIGINAL  RECOMMENDATIONS   FOR   CORKBOARD   THICKNESS 

Temperatures  Thickness 

—20°  to  —  S°    F 8  inches 

—  S°  to    +5°    F 6  inches 

S°  to       20°    F 5  inches 

20°  to        35°    F 4  inches 

35°  to        45°    F 3   inches 

45°  and    above       2  inches 

For  the  bottom  of  freezincj  tanks,  five  inches  or  preferably  six 
inches  of  .  .  .  corkboard  should  be  employed;  around  the  sides  the 
same  thickness  of  corkboard,  or  twelve  inches  of  granulated  cork 
securely  tamped   in   place. 

The  method  of  arri\ing  at  these  recommendations  mig-ht 
not  now  conform  with  the  data  and  information  available,  but 
the  experience  of  man_v  years  has  taught  that  these  recom- 
mendations for  pure  corkboard  were  then  sound  to  a  remark- 
al)le  degree. 

Reference  has  previously  been  made  to  a  class  of  insulation 
i:s:rs  who  came  to  believe  that  it  Avas  not  profitable  to  employ 
as  much  insidation  as  rec(^mmended  by  responsible  manufac- 
turers, or  wlio  came  to  believe  that  cheaper  materials  in  about 
tlie  same  thicknesses  would  suffice.  It  was  pointed  out  that 
the}-  were  much  in  the  minority,  yet  their  numbers  justified 
consideration  of  their  policy. 

The  factors  that  influence  this  class  of  buyers  are: 

(h)   Uncertainty  as  to  the  success  of  the  undertaking. 

(b)  Building  on  leased  property,  or  building  on  owned  property 
the  value  and/or  utility  of  which  is  subject  to  quick  change. 

(c)  Excess  refrigerating  machine  capacity  available. 

(d)  Insufficient   initial   funds   available   for   best   equipment. 

(e)  Expansion  as  part  of  plan  to  prepare  business  for  sale,  con- 
solidation or  refinancing. 

(f)  Work  in  charge  of  an  architect,  engineer  or  contractor  who 
follows  the  practice  of  specifying  materials  and  labor  of  but 
average  quality  for  the  sake  of  wide  competition  and  the 
lowest  price. 

(g)  Influence  of  the  practices  of  the  business  being  conducted, 
such  as  one  offering  average  or  indififerent  quality  product  at 
average  or  low  prices,  upon  the  purchase  of  products,  sup- 
plies and  equipment. 

(h)  Lack  of  true  knowledge  of  the  importance  of  adequate  refrig- 
eration and  insulation  equipment. 


184 


CORK  INSULATION 


91. — Proper  Thickness  of  Corkboard  to  Use. — The  original 
recommendations  for  pure  corkboard  insulation  need  be 
changed  only  slightly  to  bring  them  up  to  date,  as  follows : 


PROPER  THICKNESS  OF  CORKBOARD. 

Temperatures 
-20°   to        10°   1? 

Thickness 
.12   inches 

_  S"  F      

5°    to 

0°    F 

.    &  inches 

0°    to 

IQo   F                              

.  .    7  inches 

20°    F 

20°    to 

30°    F                                                  

. .    5  inches 

40°   F      

40°   to 

50°   F 

.  .    3   inches 

50°    and 

above      

.  .    2  inches 

This  table  is  predicated  on  a  useful  expectancy  for  corkboard 
insulation  of  about  fifteen  yearsf,  an  ideal  condition  of  prod- 


FIG.    55.— VOGT   INSULATION    DETAILS   FOR  NEW   FREEZING   TANK   AND 
ICE    STORAGE    ROOM. 

uct  Stored,  and  a  depreciation  in  thermal  insulation  efficiency 
of  not  to  exceed  10  per  cent  for  the  useful  expectancy  period. 
Such  table  follows  very  closely  the  general  practice  of  today, 
by  the  majority  of  insulation  users,  whose  experience  and 
judgment  has  taught  them  that  generous  thicknesses  of  only 
the  best  insulating  materials  are  profitable  in  the  long  run 
to  install. 


tThis  time   limit   fixed   bv   anticipated  obsolescence, 
life  of  the  corkboard  insulation. 


rather   than   by  the   probable 


STRUCTURAL  SUGGESTIONS 


185 


92. — Importance  of  Proper  Insulation  Design. — It  is  now 

customary,  when  planning  an  ice  or  a  cold  storage  plant,  to 
treat  the  entire  project  as  a  whole,  so  that  location,  building, 
cold  rooms,  mechanical  equipment,  and  complete  cost  are  all 
properly  balanced  and  correlated,  to  the  end  that  the  purpose 
and  intent  of  the  undertaking  can  be  fully  and  satisfactorily 
carried  out.     Such  a  project  should  be  entrusted  only  to  reli- 


(LCVOTCM     SECTION  I 


FIG.   56.— TYPICAL   SUB-STATION  FOR  STORAGE  AND  HANDLING  OF  ICE, 
INSULATED  WITH  4-IN.  CORKBOARD. 

able  architects  and  engineers  competent  to  handle  cold  storage 
work;  and  if  so  entrusted,  the  design  of  the  insulation  should 
have  that  major  attention  that  its  importance  and  cost  entitles 
it  to  receive. 

Each  new  ice  plant  and  each  new  cold  storage  plant  will 
present  its  own  peculiar  problems  in  design  and  equipment; 
but  the  field  of  insulation  experience  is  now  so  very  broad  and 
has  yielded  up  so  many  lessons,  especially  lessons  in  what  not 
to  do,  that  no  architect  and  engineer  who  is  really  experienced 
in  the  design  and  operation  of  such  plants  need  longer  be  in 
doubt  as  to  the  proper  insulating  material  to  use  and  the 
proper  insulation  specifications  to  employ.  It  must  never  be 
forgotten,  however,  that  insulation  is  a  branch  of  engineering 
and  construction  that  is  highly  specialized,  and  an  architect's 


186  CORK  INSULATION 

license  alone  is  in  no  sense  a  sufficient  recommendation  for 
the  handling  of  an  ice  or  cold  storage  project.  Here,  as  in 
most  cases  of  specialized  building  construction,  it  will  pay 
to  engage  the  architect  and  engineer  who  has  had  considerable 
experience  in  cold  storage  work. 

But  in  addition  to  the  insulation  that  is  built  into  ice  and 
cold  storage  plants  as  part  and  parcel  of  their  original  design, 
there  are  innumerable  small  insulated  cold  storage  rooms 
and  groups  of  rooms  designed  and  built  for  use  in  connection 
with  commercial  refrigerating  machines,  which  units  are  in- 
stalled as  adjuncts  to  businesses  usually  handling  food  prod- 
ucts in  one  form  or  another.  Such  installations  are  made  to 
serve  the  local  needs  of  the  individual  business,  —  such  as 
creameries,  dairies,  fruit  storages,  produce  houses,  poultry 
and  ^gg  plants,  meat  markets,  groceries,  hotels,  clubs,  hos- 
pitals, oil  refineries,  candy  factories,  ice  cream  factories,  and 
so  forth, — and  in  connection  with  the  installation  of  which 
no  architect  or  engineer  is  usually  employed.  Among  such 
rooms  there  is  a  great  variety  of  shape  and  size,  design  and 
arrangement,  method  of  cooling,  and  so  forth ;  because  a 
variety  of  purposes  must  be  served  by  rooms  built  into  every 
sort  of  structure,  under  many  different  conditions ;  and  such 
rooms  can  here  be  discussed  first  as  a  class  and  then  special 
features  treated  separately  as  they  may  apply  in  certain  cases. 

For  many  years  the  order  for  planning  such  a  cold  storage 
room,  after  deciding  on  its  location  and  size,  was  to  consider 
first  its  refrigeration  and  then  how  it  was  to  be  designed  and 
insulated.  The  order  is  now  reversed,  in  most  cases,  with 
excellent  results ;  because  it  is  today  better  understood  that 
the  efficiency  of  the  insulation  determines  in  great  degree  the 
amount  of  refrigeration  that  is  required  and  how  it  should 
be  applied.  It  has  been  seen  how  the  kind  of  insulation  that 
goes  into  a  cold  storage  room  has  a  direct  bearing  not  only 
on  the  amount  of  the  initial  investment,  but  also  on  the  every- 
day cost  of  operation,  yearly  repairs,  etc.  The  design  of  the 
room,  however,  is  equally  important;  because  the  very  best 
insulation  will  be  inefifective  and  short  lived  unless  it  is  prop- 
erly installed,  following  correct  design.  Thus  in  planning 
cold  storage  rooms,  provision  must  first  be  made  for  their 


STRUCTURAL  SUGGESTIONS 


187 


adequate  insulation,  for  on  this  feature  more  than  any  other 
will  depend  their  permanence  and  the  economy  and  efficiency 
of  their  operation. 

93. — Types  and  Design  of  Cold  Storage  Rooms. — It  is  well 
known  that  cold  storage  rooms  and  groups  of  rooms  are 
required  for  ice  making  and  ice  storage,  creameries  and  dairies, 
fruit  and  produce  houses,  poultry  and  egg  plants,  fish  and 
meat    markets,    groceries    and    ])rovisioneries,    candy    and    ice 


FIG.    57.— BAKER    PLAN    FOR   INSULATED   ROOMS    IN    OLD    BUILDING. 

cream  factories,  hotels  and  clubs,  hospitals  and  sanitariums, 
precooling  and  canning  plants,  oil  and  gasoline  refineries, 
waxed  paper  and  paraffin  coating  establishments,  fur  and  gar- 
ment storages,  brewing  and  bottling  plants,  battery  and  igni- 
tion testing  rooms,  serum  and  vaccine  rooms,  sharp  freezers 
and  hardening  rooms,  and  so  forth.  These  rooms  may  readily 
be  divided  into  two  main  classes ;  that  is,  those  operating 
above  freezing  temperature,  and  those  operating  below 
freezing:. 


188  CORK  INSULATION 

In  new  structures,  cold  storage  rooms  to  operate  at  any 
desired  temperature  can  be  made  the  exact  shape  and  size 
desired,  and  in  every  way  suited  to  their  purpose ;  but  the 
majority  of  cold  storage  rooms  operating  above  freezing — 
usually  serving  the  purpose  of  the  storage  or  handling  of  food 
products — are  erected  in  existing  buildings,  and  must  be  con- 
formed to  structural  limitations.  The  design  of  cold  storage 
rooms  employing  pure  corkboard  insulation  is  so  very  adapt- 
able, however,  in  experienced  hands,  that  there  are  virtually 
no  restrictions  on  the  construction  of  such  rooms.  Space, 
shape,  height,  location,  kind  of  building,  single  room  or  a 
group  of  rooms ;  it  is  all  "grist  for  the  mill"  when  the  basic, 
underlying  principles  of  insulation  design  are  understood. 

The  two  chief  points  to  be  kept  in  mind  in  the  design  of 
cold  storage  rooms  are :  First,  the  principle  of  no  voids  or 
air  spaces  in  or  back  of  the  insulation  ;  and,  secondly,  the 
principle  of  ample  air  circulation  within  the  cold  room.  The 
principle  of  no  air  spaces  in  or  back  of  the  insulation  is  of 
primary  importance  when  rooms  are  to  operate  below  freezing, 
and  the  principle  of  ample  air  circulation  is  of  primary  impor- 
tance when  rooms  are  to  operate  above  32°  F.,  although  both 
principles  are  of  major  importance  in  either  case. 

The  first  principle,  that  of  no  voids  or  air  spaces  in  or 
back  of  the  insulation,  is  especially  important  where  cold 
storage  rooms  are  to  operate  below  freezing,  because  of  the 
greater  likelihood  of  colder  temperatures  back  of  the  insula- 
tion and  the  consequent  greater  likelihood  of  condensed  water. 
If  there  are  no  voids  in  the  insulation  itself,  no  voids  in  the 
finish  applied  to  the  surface  of  the  insulation,  no  voids  in 
the  material  used  to  bond  the  insulation  to  the  surfaces  to 
which  it  is  applied,  no  voids  or  open  cracks  between  the  sheets 
of  corkboard,  no  voids  or  air  pockets  in  the  construction  of 
the  building  walls  themselves,  no  voids  anywhere,  the  result 
will  be  a  perfect  insulation  job,  assuming  such  perfect  condi- 
tions obtainable ;  for  all  such  voids  and  air  spaces  are  likely 
to  fill  up  with  water,  through  condensation  of  moisture  from 
the  air  against  chilled  surfaces,  and  deterioration  and  lowered 
insulation  efficiency  will  be  the  certain  result. 

In  practice,  the  aim  is  for  that  which  is  as  near  perfection 


STRUCTURAL  SUGGESTIONS  189 

as  is  consistent  with  a  variety  of  conditions,  costs,  and  so 
forth.  If  possible,  walls,  floors  and  ceilings  should  be  of  solid 
construction,  that  is,  without  voids  or  air  spaces,  as  solid  brick 
or  concrete  in  preference  to  hollow  tile  or  sheathed  studs  and 
joists.  The  air  in  such  spaces  contains  moisture  in  suspension, 
which  is  likely  to  be  condensed  on  the  cool  surfaces  next  to 
the  cold  temperature  room*;  and  as  the  water  contained  in 
the  air  in  such  spaces  condenses,  it  occupies  as  a  liquid  less 


FIG.   58.— SAUSAGE  COOLER  WITH  STATIOxNARY  AND   PORTABLE  RACKS, 
TRACKING   AND    OVERHEAD    BUNKERS. 

space  than  it  did  as  a  vapor,  an  uneven  pressure  is  set  up  or 
partial  vacuum  created,  more  air  containing  moisture  of  pro- 
portion indicated  by  its  humidity  is  drawn  in,  more  precipita- 
tion takes  place,  and  if  there  is  then  no  opportunity  for  such 
water  deposits  to  quickly  evaporate  away  again,  all  such 
spaces  will  be  the  source  of  "moisture  trouble."    Such  moist- 


*Dirty  lath  streaks  on  ceilings  of  offices,  residences,  etc.,  furnish  a  g9od  example 
of  the  precipitation  of  moisture  from  the  air  against  cool  surfaces.  In  winter  the  air 
above  the  wood  lath  and  plaster  is  often  cooler  than  the  air  of  the  room;  and,  as  a 
result,  moisture  is  condensed  on  the  cool  strips  of  plaster  between  the  lath,  and 
minute  particles  of  dust  are  caught  in  this  moisture. 


190 


CORK  INSULATION 


ure,  in  closed-in  spaces,  may  be  the  cause  of  all  sorts  of 
building  construction  troubles,  such  as  rotting,  and  bulging 
and  cracking  from  uneven  expansion ;  but  our  thought  will 
be  primarily  for  the  damage  to  the  insulation  itself.  In  the 
case  of  ceilings  especially,  the  water  slowly  finds  its  way  into 
the  insulation  underneath,  and  failure  of  that  ceiling  insula- 
tion will  be  the  certain  result.  Where  such  construction  can- 
not be  avoided,  all   such   spaces   should  be   left   as   open   as 


FIG.    59.— ICE    CREAM    HARDENING    ROOM    WITH    PERFORATED    PLATES 
OVER  PIPE  SHELVES. 

possible  SO  that  air   may   circulate   freely  through  them   and 
thus  carry  ofif  by  evaporation  any  condensed  moisture. 

The  second  principle,  that  of  ample  air  circulation,  is  even 
more  important  in  cold  storage  rooms  operating  above  freez- 
ing than  it  is  in  rooms  maintaining  lower  temperatures ;  be- 
cause refrigeration  in  its  simplest  terms  is  the  extraction  and 
removal  of  heat  from  the  goods  stored,  which  is  done  not  by 
immediate  contact  between  the  goods  and  the  refrigerant  but 
through  the  medium  of  the  air,  and  in  rooms  operating  above 


STRUCTURAL  SUGGESTIONS  191 

freezing  the  moderately  cooled  air  does  not  drop  to  the  floor 
of  the  room  as  swiftly  as  if  it  were  chilled  to  a  lower  tem- 
perature. That  is,  in  rooms  operating  above  freezing,  the  air 
circulation  is  naturally  sluggish,  although  the  process  of  heat 
interchange,  by  means  of  the  positive  circulation  of  the  air, 
is  essential.  Room  design  must  therefore  promote  air  circu- 
lation as  much  as  possible,  to  keep  it  positive  and  active, 
especially  in  rooms  used  for  products  containing  much  moist- 
ure, such  as  butter,  poultr}-  and  meats,  particularly  if  such 
products  are  put  in  warm  for  quick  chilling;  because  such 
moisture  must  be  taken  up  by  the  circulating  air  and  carried 
quickly  to  the  coils  and  there  deposited  as  frost.  Otherwise, 
with  poor  circulation,  moisture  will  condense  on  the  finish  of 
the  insulated  surfaces,  on  the  goods  stored,  or  remain  in  the 
air  of  the  room  to  make  it  damp  and  mouldy. 

94. — Types  of  Bunkers  and  Details  of  Construction. — The 

one  positi\e  way  to  guarantee  a  definite  circulation  of  air 
throughout  a  cold  storage  room  is  to  construct  a  separate 
cooling  room,  or  coil  bunker  room,  install  air  conveying  ducts 
from  the  coil  room  to  and  into  the  cold  storage  room,  and  by 
means  of  blower  equipment  circulate  or  pass  the  air  of  the 
cold  storage  room  through  the  system  and  over  the  cooliiig 
coils  at  a  predetermined  rate.  This  method  of  positive  circu- 
lation, or  cold  air  distribution,  is  frequently  employed  in  fur 
rooms,  candy  dipping  rooms,  freezing  rooms,  or  wherever  the 
demand  justifies  the  initial  expense  for  such  extra  equipment 
and  the  cost  of  its  subsequent  operation. 

By  far  the  most  effective  natural  means  of  insuring  active 
circulation  is  the  overhead  bunker.  Air,  cooled  over  such 
bunker  by  contact  with  the  cooling  coils  or  ice,  falls  over  the 
low  side  of  the  bunker  and  to  the  floor,  due  to  the  fact  that 
cold  air  is  heavier  than  the  warmer  air  it  displaces ;  and  as  this 
cold  air  absorbs  the  heat  of  the  goods  stored  as  well  as  the 
heat  that  leaks  into  the  room  through  the  insulation,  doors, 
etc.,  such  air  rises  over  the  high  side  of  the  bunker,  circulates 
through  the  coils  or  over  the  ice,  gives  up  its  excess  of  heat 
to  the  refrigerant,  and  begins  the  cycle  over  again.  Thus  the 
circulation  follows  its  natural  course,  and  as  the  bunker  ex- 
tends the  length  of  the  room,  the  air  circulation  reaches  every 


192 


CORK  INSULATION 


corner  of  the  room  and  maintains  a  fairly  uniform  temperature 
in  practically  all  parts. 

Single  overhead  bunkers  are  the  most  common  type,  but 
should  not  be  used  for  rooms  over  16  feet  in  width.  For 
rooms  wider  than  16  feet,  double  bunkers  should  be  installed. 
The  bunker  construction  serves  to  guide  the  circulating  air, 
and  this  function  is  greatly  assisted  by  proper  bunker  design. 
First,  the  warm  air  up-take  and  the  cold  air  down-flow  must 


FIG.    60,— cox    HOLDOVER   TANK    COOLING    SYSTEM.    ILLUSRAT- 

IXG    PLAN   DETAILS    OF    BUNKER    CONSTRUCTION 

AND   CORKBOARD   INSULATION. 

be  adequate;  a  "rule-o'-thumb"  method  that  has  given  excel- 
lent results  in  rooms  operating  above  freezing  is  to  make  the 
total  width  of  these  duct  openings  equivalent  to  one-third  of 
the  total  width  of  the  room,  and  then  divide  that  one-third 
equally  between  the  warm  and  the  cold  air  ducts.  Care  should 
then  be  exercised  not  to  "choke"  the  circulation  at  any  point 
in  the  bunker  construction  between  the  warm  air  entrance 
and  the  cold  air  exit,  either  by  restricting  the  passage  by 
decreased  dimensions,  or  by  obstructing  it  by  a  crowded 
arrangement  of  coils  or  ice,  or  by  counter  air  currents  set 


STRUCTURAL  SUGGESTIONS 


193 


up  by  failure  to  use  sufficient  insulation  on  the  bottom*  and 
baffle  of  the  bunker. 

The  overhead  bunker,  single  or  multiple  type,  requires 
considerable  head  room,  a  10-foot  height  before  the  insulation 
is  erected  on  floor  and  ceiling  being  necessary  for  a  maximum 
head  room  of  6  feet  under  bunker  and  a  coil  loft  maximum 
height  of  2^  feet,  A  minimum  height  of  12  feet  before  insu- 
lation is  applied  is  much  better,  especially  if  ice,  which  re- 


m 


FIG.  61.— COX   HOLDOVER  TANK  COOLING  SYSTEM.  ILLUSTRATING  ELE- 
VATION DETAILS  OF  BUNKER  CONSTRUCTION  AND  CORKBOARD 
INSULATION. 

quires  more  head  room  than  coils,  is  to  be  used.  If  the  room 
is  to  contain  overhead  tracking,  additional  height  will  be 
necessary.  The  natural  arrangement  of  double  bunkers  is 
to  place  each  warm  air  up-take  next  a  side  wall  and  the  cold 
air  down-flow  in  the  center  of  the  room ;  because  the  warmest 
air  in  the  cold  storage  room  is  likely,  on  account  of  the  heat 
leakage,  to  be  a  layer  adjacent  to  the  walls.  In  certain  cases, 
however,  such  as  chill  rooms  for  fresh  killed  poultry  or  pre- 
coolers  for  fresh   beef,   this   warm   and   cold   air   duct  order 


•Sufficient  insulation   on  the  bottom  of  bunker  will  also   prevent  sweating. 


194 


CORK  INSULATION 


should  be  reversed ;  because  the  greater  temperature  will  then 
come  from  the  fresh  goods  stored  in  the  room,  away  from 
the  walls,  and  the  natural  circulation  will  be  through  a  warm 
air  up-take  in  the  center  of  the  room  and  down  at  either  side. 

In  the  case  of  a  single  bunker,  the  warm  air  up-take  should 
be  on  the  entrance  door  side  of  the  cold  storage  room,  so  that 
the  in-flow  of  warm  air  occasioned  by  the  opening  of  the  cold 
storage  door  will  be  carried  up  and  over  the  bunker  before 
coming  in  contact  with  the  goods  stored  in  the  room. 

Where  the  available  ceiling  height  does  not  permit  of  over- 
head bunkers,  the  side  or  wall  bunker  may  be  used,  though 
it  is  much  less  effective,  except  in  narrow  rooms,  a  width  of 
12   feet   probably   being  the   ultimate  limit   for  a   single   wall 


O  O  O  O  O  O  O  O  O  '    •'  ''  r    -, 
O  O  O  O  O  O  O  C-  O  O  O  C;  O  O 

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oooooooooooooo 


FIG.    62.— SECTION    OF    TYI'ICAL    SINGLE    OVERHEAD    COIL    BUNKER. 

bunker.  ^Vider  rooms  of  limited  ceiling  height  should  have 
wall  bunkers  along  both  sides,  but  not  along  one  side  and  one 
end. 

Low  rooms  employing  mechanical  refrigeration,  frequently 
use  ceiling  or  wall  coils,  or  both,  instead  of  the  side  bunker, 
provided  the  cold  storage  room  does  not  contain  too  much 
moisture  requiring  an  active  and  positive  circulation  to  dispose 
of  it  as  frost  on  the  cooling  coils.  Drip  pans  under  ceiling 
coils  and  open  drain  spouting  under  wall  coils  should  be  pro- 
vided to  care  for  the  water  of  meltage.  Very  wide  rooms 
and  rooms  used  for  long  storage,  more  often  use  ceiling  coils 
than  bunkers,  regardless  of  the  height  available;  such  ceiling 


STRUCTURAL  SUGGESTIONS 


195 


coils  are  grouped  and  the  groups  spaced  at  proper  distances, 
each  group  equipped  with  an  insulated  drip  pan,  a  modified 
form  of  overhead  bunker.  The  arrangement,  when  both  ceil- 
ing and  wall  coils  are  used,  should  never  include  an  installa- 
tion of  piping  on  ceiling,  one  side  wall  and  one  end  wall ;  but 
should  be  limited  to  ceiling  and  one  or  both  side  walls,  so  as 
to  avoid  cross  or  counter  currents  and  consequent  poor  air  cir- 
culation and  "pockets."  Where  wall  coils  only  are  used,  the 
coils  should  be  located  on  opposite  side  walls,  or  equally  dis- 


FIG.  63.— DETAIL  OF  HENSCHIEN  PIPE  LOFT  FOR  HOG  COOLER. 

tributed  on  all  four  walls,  the  shape  of  the  room  as  it  may  or 
may  not  depart  from  a  square  being  the  governing  factor. 


95. — Circulation,  Ventilation  and  Humidification. — A  good 
deal  has  previously  been  said  about  the  necessity  for  air  cir- 
culation in  cold  storage  rooms,  but  the  subject  shall  now  be 
briefly  considered  in  conjunction  with  the  ventilation  and 
humidification  of  rooms  used  for  the  handling  and  storage  of 
certain  products. 

The  question   of  the   hygrometric  condition  of  the  air  in 


196 


CORK  INSULATION 


cold  storage  rooms,  especially  in  refrigerated  warehouses,  is 
of  much  importance  for  satisfactory  results  in  the  preservation 
of  various  kinds  of  foods,  such  as  fruits,  meats,  eggs,  etc. 
Humidity  is  now  believed  by  many  to  be  almost  as  important 
as  temperature  itself;  and  this  conviction  coupled  with  the 
further  recognition  of  the  desirability,  if  not  the  necessity,  for 
the  ventilation  of  rooms  containing  certain  products,  makes 
circulation,  ventilation  and  humidification  of  cold  rooms  an 
important,  and  it  may  be  said  an  involved,  subject. 

It  is  a  well-known  fact  that  meat  cannot  stand  a  higher 
temperature  than  the  freezing  point,  without  it  undergoes  a 
continuous  evaporation  through  its  surface,  unless  the  humid- 
ity of  the  cold  room  is  kept  sufficiently  low.     For  eggs,  the 


oooo 
oooo 
oooo 
oooo 
oooo 
oooo 
oooo 
oooo 
oooo 
oooo 
oooo 

1 

FIG.    64.— SECTION    OF   TYPICAL    SIDE   BUNKER   ARRANGEMENT    FOR 
SMALL  ROOM   OF   RESTRICTED  HEIGHT. 


air  must  be  kept  at  a  higher  degree  of  moisture  than  for  meat. 
For  fresh  fruits,  the  air  must  be  moist  enough  to  prevent  the 
drying  out  of  the  fruit  due  to  excessive  surface  evaporation, 
while  at  the  same  time  the  air  must  not  be  too  moist  if  decay 
is  to  be  avoided. 

Thus  with  some  products  it  is  essential  for  best  results 
that  some  form  of  ventilation  and  humidification,  or  air  con- 
ditioning, be  provided  in  cold  storage  rooms  to  prevent  evapo- 
ration and  spoilage ;  and  the  proper  design  and  insulation  of 
such  rooms  is  even  more  important  than  that  of  the  regular 
run  of  cold  storage  rooms.  The  question  of  the  proper  method 
and  equipment  to  use  for  the  air  conditioning  of  cold  storage 
rooms  will  not  be  treated  in  this  text,  although  permission 
has  been  given  for  the  partial  reproduction  of  an  article,  whic 


STRUCTURAL  SUGGESTIONS 


197 


should  be  of  general  interest  at  this  point,  on  the  subject  of 
"Temperature,  Humidity,  Air  Circulation  and  Ventilation," 
by  M.  R.  Carpenter,  Architect  and  Refrigerating  Engineer, 
72  W.  Washington  St.,  Chicago,  Illinois : 

During  the  past  ten  years,  or  thereabout,  the  subject  of  air  con- 
ditions in  cold  storage  has  been  receiving  considerable  attention  from 
those  who  are  in  a  position  to  recognize  the  shortcomings  of  the  aver- 
age cold  storage  plant  as  a  means  of  holding  and  preserving  edible 
products,  during  the  time  of  storage. 


FIG.  65.— INSULATED  MEAT  COOLER  ON  BLUE  STAR  LINE  S.  S.  ALAMEDA, 
SHOWING  INSTALLATION  OF  PIPING  ON  CEILING  AND  ALL  WALLS. 


Many  things  are  involved  in  the  successful  preservation  of  such 
commodities  and  it  is  for  the  purpose  of  calling  attention  to  these 
various  items  that  this  paper  is  written. 

As  a  rule,  cold  storage  plants  represent  the  expenditure  of  large 
sums  of  money  and  are  owned  and  operated  by  conservative  business 
men,  who  have  to  be  shown  before  they  will  adopt  any  new  system, 
or  attempt  to  maintain  any  condition  in  their  cold  storage  rooms 
which  has  not  been  proved  to  them  to  be  desirable  in  practical  use. 
This  is  good  business  policy,  as  failure  would  mean  the  loss  of  enor- 
mous sums  in  spoiled  goods,  which  they  would  have  to  assume,  due 
to  such   experiments. 


198 


CORK  INSULATION 


In  the  early  days  of  cold  storage,  the  first  consideration  was  tem- 
perature, and  the  designers  of  such  plants  gave  little  thought  to  other 
features.  This  is  still  true,  for  that  matter,  with  a  large  majority,  as 
may  be  noted  by  examination  of  many  storages,  and  by  the  fact  that 
practically  all  contract  forms  issued  by  manufacturers  of  refrigerating 
machinery  guarantee  temperatures  and  nothing  further,  inside  of  the 
rooms;  but  practice  soon  proved  that  other  things  were  important, 
especially  as  some  storages  were  damp  and  musty,  which  was  disas- 
trous to  the  goods,  due  to  the  growth  of  fungi  or  mould;  therefore,  it 
was  found  desirable  to  adopt  measures  to  avoid  this  condition,  and 
the  next  step  was  in  the  direction  of  obtaining  cold,  dry  rooms;  this 
was   accomplished   either   by   properly   loratine  the   refrigerating   coils 


FIG.    66.— CORKBOARD    INSULATED    CHOCOLATE    DIPPING    ROOM    WITH 
COLD    AIR    DUCT    CIRCULATING    SYSTEM. 

or  by  some  method  of  drying  the  air,  by  means  of  lime  or  calcium 
chloride;  the  various  methods  for  accomplishing  this  are  familiar  to 
all,  especially  the  older  heads. 

Experience  showed  that  the  design  of  the  refrigerating  coils  and 
the  location  of  them  in  the  rooms  to  be  cooled  had  a  material  bearing, 
both  on  the  efiiciency  of  the  cooling  effect  and  on  the  humidity  of  the 
air;  this  was  to  have  been  expected  as  it  follows  out  a  simple  law  of 
nature  which,  when  adhered  to  consistently,  results  in  an  extremely 
dry  atmosphere. 

This  dry  condition  naturally  leads  to  shrinkage,  or  evaporation  of 
the  moisture  from  the  goods,  which,  if  it  was  allowed  to  proceed 
beyond  a  certain  point,  caused  trouble  of  another  type;  therefore,  it 
was  found   desirable  to  maintain  a  certain  amount   of  humidity;  and 


J 


STRUCTURAL  SUGGESTIONS  199 

many  practical  experiments  were,  and  still  are,  being  made,  to  deter- 
mine to  just  what  extent  relative  humidity  can  be  carried  before  it 
becomes  objectionable  and  dangerous  in  other  respects;  this  led  to 
many  differences  of  opinion,  as  each  example  of  practical  results  was 
modified  by  specific  conditions  pertaining  particularly  to  the  individual 
room;  these  conditions  were  not  fully  understood  or  taken  into  con- 
sideration in  the  conclusions;  therefore,  a  certain  relative  humidity, 
which  proved  correct  or  beneficial  in  one  room,  or  house,  proved 
incorrect  in  another;  then,  too,  the  method  and  manner  employed  for 


FIG.    67.— MEAT    STORAGE'  COOLER    WITH    OVERHEAD    TRACKING    AND 
COIL  ROOM   ABOVE. 

determining  humidity  was  often  open  to  question,  as  was  also  the 
correctness  of  the  determination. 

Humidity  determinations  taken  in  a  room  are  often  of  no  value  in 
fixing  the  relative  humidity  immediately  surrounding  the  goods,  due 
to  sluggish  air  movement  or  definite  pocketing  of  the  surrounding  air, 
such  as,  for  instance,  goods  contained  in  tight  barrels  or  other  tight 
or  semi-tight  packages,  goods  wrapped  in  paper,  or  goods  piled  tight, 
without  channels  between  them. 

As  a  rule,  there  is  very  little  trouble  encountered  in  securing 
humidity;  the  difficulty  lies  in  controlling  it  and  maintaining  it  con- 
stant; therefore,  the  tendency  is  to  proceed  very  carefully  and  not 
overdo  it. 


200  CORK  INSULATION 

Until  comparatively  recent  years,  there  has  been  no  reliable  data 
on  which  to  proceed  in  a  practical  way.  It  is  true  that  experiments 
have  been  made  for  years;  some  along  the  line  of  best  temperatures 
for  particular  goods,  some  for  humidity  in  relation  to  shrinkage, 
humidity  in  relation  to  mould,  etc.,  and  these  experiments  have  been 
made  by  individuals  fully  qualified  and  capable  of  carrying  on  such 
work.  Especially  is  this  true  of  the  experiments  made  by  the  United 
States  Department  of  Agriculture;  however,  in  most  cases  there  has 
been  a  lack  of  some  certain  conditions,  or  combination  of  conditions, 
either  through  lack  of  knowledge  of  new  factors  entering  into  the 
experiment,  or  through  a  lack  of  eflficient  apparatus  to  fully  cover  all 
requirements.  No  criticism  of  these  experiments  is  implied,  for  every 
one,  when  made  with  care,  has  brought  us  nearer  to  a  solution,  and 
a  step-by-step  advancement  in  this  art  is  a  surer  way  than  to  try 
everything  at  once. 

It  probably  is  universally  conceded  that  all  vegetable  products 
have  a  definite  life  limit,  during  which  time  they  function  as  living 
organisms,  absorbing  or  breathing  in  certain  gases  and  exhaling,  or 
giving  off  certain  other  gases  or  esters,  during  which  period  they 
continue  to  develop  and  change  until  their  physical  development  is 
complete  and  their  life  span  is  ended,  after  which,  especially  in  the 
case  of  fruits,  they  are  spoken  of  as  being  dead  ripe. 

Assuming  the  foregoing  facts  to  be  true,  one  may  readily  appre- 
ciate how  necessary  it  is  to  have  definite  air  circulation  to  supply 
fresh  air  to  absorb  the  heat,  as  well  as  to  remove  the  gases  given  off, 
or  ejected,  by  the  goods. 

No  vegetable  products,  in  the  natural  state,  are  of  the  same  food 
value  after  becoming  dead  ripe,  as  they  are  at  some  stage  prior  to 
reaching  that  state,  after  which  no  temperature  or  other  cold  storage 
condition  will  prevent  them  from  deteriorating  at  a  rapid  rate. 

Animal  products,  on  the  other  hand,  are  dead  and  any  change  is 
either  chemical  or  due  to  plant  or  animal  organisms. 

Granting  that  the  foregoing  statements  are  correct,  let  us  con- 
sider what  means  will  best  serve  to  prolong  the  life  of  fruits,  vegetables 
and  animal  products.  In  answering  this,  there  need  be  no  hesitancy 
in  stating  that  there  are  just  two  factors — correct  temperature,  and 
pure,  conditioned  air.  By  conditioned  air,  is  meant  air  containing 
the  correct  amount  of  moisture  for  the  particular  goods  under  con- 
sideration. This  sounds  rather  simple;  yet,  to  secure  these  two  con- 
ditions requires  a  knowledge  of  and  a  scientific  appreciation  of  nature's 
laws.  To  even  approach  a  state  of  perfection  in  a  practical  way, 
involves  about  all  that  is  known  at  the  present  time  regarding  correct 
design,  equipment,  and  operation  of  cold  storage  warehouses;  so  it  is 
not  as  simple  as  it  seems. 

It  may  be  well  to  consider,  at  this  time,  briefly,  the  subject  of 
temperature.  What  is  its  function?  And  pure,  conditioned  air;  what 
part  does  it  play? 


STRUCTURAL  SUGGESTIONS  201 

Temperature  aflFects  the  growth  of  living  organisms,  both  vege- 
table and  animal,  and,  when  below  the  temperature  level  best  suited 
to  this  growth,  or  development,  has  the  effect  of  slowing  them  up, 
rendering  them  dormant  or  destroying  them  entirely;  depending  upon 
the  decreasing  temperature  to  which  they  are  subjected;  therefore,  in 
the  case  of  vegetables  or  fruit  products,  their  life  span  is  increased, 
and,  in  respect  to  attack  from  the  outside,  they  are  again  protected 
by  the  dormant  condition  of  their  enemies. 

Animal  products,  which  are  dead  substances,  can  only  be  pre- 
served by  the  prevention  of  changes  due  to  attack  by  living  organisms, 
either  contained  in  but  not  a  part  of  them,  or  by  attack  from  the 
outside;  again,  as  in  the  case  of  the  vegetable  kingdom,  these  enemies 
are  rendered  less  active  as  the  temperature  decreases. 

Our  problem  may  then  be  divided  into  two  parts.  The  first  is  to 
determine  the  correct  temperature  and  relative  humidity  of  the  air, 
for  each  particular  product;  and  this  division  may  best  be  left  in  the 
hands  of  scientists,  who  have  the  proper  knowledge  and  apparatus  for 
making  scientific  tests  and  determinations  for  solution.  The  second 
involves  the  application  of  the  conditions  first  found,  and  naturally 
leads  to  the  designing  engineer,  with  the  co-operation  of  the  scientist, 
in  providing  such  construction,  apparatus  and  operation  as  will  secure 
the  correct  temperature  and  air  conditions. 

Having  been  instructed  regarding  the  proper  temperatures  and 
relative  humidity,   how  shall  we  proceed  to  secure  them? 

Temperature. 

We  shall  first  consider  temperature.  It  is  self-evident  that  if  a 
product  is  to  be  held  at  a  certain  specified  temperature,  it  is  the  tem- 
perature of  the  product  and  not  necessarily  the  temperature  of  the 
room  which  is  important. 

This  being  the  case,  how  are  we  to  insure  the  temperature  of 
the  product?  In  answer  to  this,  it  is  necessary  to  consider  the  trans- 
fer of  heat.  Heat  must  be  taken  from  the  goods  and  delivered  into 
the  refrigerant,  which  is  circulating  through  the  refrigerating  coils, 
and  this  heat  can  only  be  transferred  in  two  ways — by  conduction,  or 
by  convection. 

Heat  transfer  by  conduction  through  air  is  a  slow  process,  and 
altogether  out  of  consideration  for  practical  results;  therefore,  trans- 
fer by  convection  is  the  only  practical  method,  and  this  involves  a 
definite  air  movement,  and  the  rapidity  with  which  the  heat  is  trans- 
ferred is  in  direct  proportion  to  the  rapidity  of  the  air  movement 
through  the  goods,  to  and  over  the  refrigerating  coils  and  back  to  the 
goods. 

There  are  two  methods  of  circulating  air,  one  way  being  to  take 
advantage  of  what  is  called  natural  circulation,  that  is,  air  movement 
in  a  vertical  direction,  due  to  the  difference  in  temperature,  or  specific 
gravity,    which    method   is   slow,    uncertain,   and   with   little   power   to 


202  CORK  INSULATION 

overcome  obstacles,  to  reach  out  into  pockets  and  crevices,  or  to 
move  through  piled  goods  in  any  direction. 

The  other  method  is  by  means  of  mechanically  moved  or  forced 
air  circulation,  which  is  powerful  and  active  in  entering  into  all 
crevices,  pockets,  etc.,  and  which  moves  through  goods  in  any  direc- 
tion, thereby  taking  up  the  heat  from  the  interior  of  packages,  as  well 
as  from  the  outside,  and  is  therefore  efficient  in  securing  quick  transfer 
of  heat. 

From  the  foregoing  it  will  be  noted  that  the  only  practical  method 
of  insuring  the  proper  temperature  of  goods  in  storage  appears  to 
be  to  subject  them  to  a  forced  air  circulation,  due  consideration  to  be 
given  to  proper  piling,  ventilated  crates,  etc.,  and  with  means  of  con- 
trolling the  intensity  of  the  air  movement. 

Air  and  air  movement  are  considered  in  the  foregoing  only  as  a 
medium  for  holding,  and  a  method  of  conveying  the  heat  units  from 
the  goods  to  the  refrigerating  coils;  later  we  shall  utilize  this  same  air 
and  air  movement   for  another  purpose. 

Pure  Conditioned  Air. 

The  second  condition  essential  for  the  preservation  of  goods  is  to 
surround  them  with  air  which  is  free  from  all  foreign  gases,  dust, 
germs,  spores,  bacteria,  etc.,  but  with  sufficient  moisture  content  to 
prevent  the  absorption  of  the  natural  moisture  content  of  the  goods, 
as  otherwise  they  would  be  caused  to  shrink,  which  is  not  only  objec- 
tionable in  itself,  but,  in  the  case  of  vegetable  products,  also  causes 
them  to  become  more  susceptible  to  attack  from  other  sources,  and 
hastens  the  breaking  down  of  the  whole  organic  structure. 

Pure  air  not  only  insures  against  contamination  from  the  exterior, 
but  has  a  decided  purifying  effect  in  itself. 

To  surround  goods  with  pure  air  and  correct .  moisture  content, 
it  is  not  sufficient  to  merely  maintain  this  condition  in  the  open  parts 
of  the  room;  because,  as  in  the  consideration  of  temperature,  it  is  the 
products  themselves  which  must  be  considered,  and  the  air  in  the  room 
is  only  an  approximate  indication,  depending  largely  upon  the  circula- 
tion of  the  air. 

As  in  the  example  under  temperature,  natural  circulation  is  very 
slow  and  without  the  power  to  penetrate  deeply;  therefore,  air  be- 
comes pocketed,  in  which  condition  it  absorbs  moisture  from  the 
goods  until  it  becomes  fully  saturated;  it  also  absorbs  gases  or  esters 
and,  as  a  result,  becomes  foul,  the  natural  effect  of  which  is  to  pro- 
vide a  condition  suitable  for  the  growth  of  moulds,  fungi,  or  other 
destructive  agents,  which,  also  due  to  the  lack  of  proper  temperature, 
as  shown  before  by  sluggish  or  stagnant  air,  are  not  materially  re- 
tarded  in  their   growth. 

The  other  method — that  of  forced  air  circulation — is  positive, 
penetrating,  and  scrubbing  in  its  action.  It  prevents  any  accumula- 
tion  of  dead   air,   and   therefore   maintains   an   ideal   condition   imnie- 


STRUCTURAL  SUGGESTIONS 


203 


diatcly  in  contact  with  the  goods,  assuming,  of  course,  that  the  method 
of  packing  and  storing  the  goods  is  in  keeping  with  the  idea  of 
thorough  and  efificient  air  circulation. 

It  will  have  been  noted  that  use  of  the  term  ventilation  has  not 
been  made  in  any  of  the  foregoing,  the  term  being  considered  as  a 
description  covering  another  process. 

In  the  foregoing  subject  of  pure,  conditioned  air,  it  is  assumed 
that  the  air  being  circulated  is  pure  and  of  the  correct  relative 
humidity;  in  practice,  this  is,  of  course,  impossible,  unless  there  is 
provided  some  means  of  keeping  it  pure  and  of  the  right  moisture 
content.  The  air  is  continuously  taking  up  gases  and  odors  from 
the  goods,  as  well  as  changing  in  moisture  content,  due  to  absorption 


-INSULATED    EGG    STORAGE    WITH    OVERHEAD    BUNKERS    AND 
PATENTED    VENTILATING    SYSTEM. 


of  moisture  from  the  goods  or  depositing  it  on  the  refrigerating  coils, 
-thereby  becoming  impure  and  with  the  wrong  moisture  content,  which 
will,  in  the  course  of  time,  cause  the  air  to  become  foul  and  dangerous 
and,  in  the  case  of  forced  air  circulation,  increasingly  so,  due  to  the 
ability  to  distribute  dangerous  organisms,  spores  of  disease  germs, 
quickly  and  effectively,  unless  some  provision  is  made  for  keeping  it 
pure;  this  is  where  use  is  made  of  ventilation. 

Starting  out  with  the  storage  space  clean  and  free  from  mould  or 
objectionable  odors,  and  with  the  goods  in  a  clean  and  altogether 
suitable  condition,  the  preservation  is  dependent  more  upon  preventive 
measures  than  upon  corrective  ones,  and  it  is  a  very  simple  matter  to 
offset  or  rectify  the  slight  contamination  of  the  circulated  air,  due  to 
eliminations  from  the  goods,  by  some  system  of  ventilation,  that  is,  by 


204  CORK  INSULATION 

introducing  pure,  fresh  air,  in  sufficient  quantities,  while  discharging 
an  equal  amount  of  stale  air,  thereby  keeping  the  percentage  of  im- 
purities down  to  a  low  point.  Naturally  the  amount  of  fresh  air 
introduced  will  depend  entirely  upon  the  amount  required  to  rectify 
the  foul  condition  of  the  old  air. 

Where  forced  air  circulation  is  employed,  providing  the  equip- 
ment is  properly  designed,  the  introduction  of  fresh  air  is  a  simple 
matter. 

Normal  Humidity. 

The  control  of  moisture  content  of  the  circulating  air  is  difficult 
unless  proper  provision  is  made  for  adding  or  subtracting  moisture, 
as  occasion  demands. 

At  this  point,  the  privilege  is  taken  of  using  one  word  to  indicate 
the  proper  moisture  content  of  the  air  for  a  specific  commodity,  and 
it  is  normnl;  normal  may  mean  any  relative  humidity,  but  when  used 
in  connection  with  a  specific  commodity  it  is  a  definite  percentage;  if 
it  is  above  this  percentage,  it  is  normal-plus,  if  below,  it  is  normal- 
minus. 

Therefore,  what  may  be  normal  humidity  for  one  class  of  goods 
may  be  normal-plus  or  normal-minus  for  another. 

To  determine  what  is  normal  in  each  instance  is  the  work  of  the 
scientist,  or  it  may  be  determined  by  practical  experience,  extending 
over  a  period  of  years,  but  in  this  case  it  may  only  apply  to  a  par- 
ticular room  or  warehouse,  as  the  amount  of  moisture  which  may  be 
maintained  in  the  air  of  any  room  is  absolutely  dependent  on  the 
efficiency  of  the  air  circulating  system  and  its  ability  to  penetrate  to 
all  parts  of  the  goods,  thereby  maintaining  the  proper  temperature 
and  air  condition. 

As  before  explained,  the  air,  in  circulating  through  the  various 
channels,  is  ever  subjected  to  conditions  which  have  a  tendency  to 
vary  the  moisture  content.  The  most  severe  conditions  are:  First, 
the  goods  in  storage;  and,  second,  the  refrigerating  coils;  the  first  in 
adding  to  the  moisture  content  and  the  second  in  reducing  the  moist- 
ure content,  and,  where  ventilation  is  utilized  to  purify  the  air,  another 
condition  is  encountered,  which  may  either  increase  or  decrease  the 
humidity. 

It  has  been  proved  by  scientific  research,  as  well  as  by  practical 
experience,  that  a  certain  amount  of  moisture  in  the  air  is  not  only 
beneficial,  but  is  absolutely  necessary  to  the  preservation  of  goods; 
also,  that  under  certain  conditions,  especially  with  forced  air  circula- 
tion, it  is  absolutely  necessary  to  maintain  a  high  moisture  content 
in  the  air. 

Assuming,  therefore,  that  we  carry  a  relatively  high  humidity, 
which  will  prevent  the  air  from  taking  up  moisture  from  the  goods, 
we  have  eliminated,  to  a  large  extent,  interference  from  that  source; 
we  have  then  left  the  drying  effect  of  the  refrigerating  coils  and, 
with  forced  air  circulation,  this  is  sufficient,  practically  all  of  the  time 


STRUCTURAL  SUGGESTIONS 


205 


and  under  almost  all  conditions,  to  produce  normal-minus  humidity; 
therefore,  in  order  to  keep  the  air  up  to  normal,  it  is  usually  neces- 
sary to  introduce  moisture,  either  with  the  fresh,  ventilating  air,  oi 
with  the  recirculated  air.  In  either  case,  a  fully  saturated  air  may  be 
introduced  when  necessary,  without  danger  of  depositing  moisture  on 
the  goods,  due  to  the  fact  that  it  will  be  mixed  with  a  much  greater 
volume  of  normal-minus  air  before  coming  into  contact  with  the 
goods. 

At  certain  seasons  of  the  year,  namely,  during  periods  of  low 
temperature,  when  the  refrigerating  coils  are  not  being  used,  except 
to  a  very  limited  extent,  if  at  all  (and  therefore  their  drying  effect  is 
greatly  reduced  or  stopped  entirely),  nature  still  provides  ample  means 


FIG. 


69.— INSULATED    BANANA    ROOM    EQUIPPED    WITH    OVERHEAD 
BUNKERS  AND   PATENTED   CONTROL   SYSTEM. 


of  controlling  the  humidity,  by  furnishing  cold  air  which,  when  raised 
to  the  temperature  requirements  of  the  room,  will  be  comparatively 
dry  and  may  be  introduced  in  sufificient  volume  to  offset  other  con- 
ditions, and  thus  maintain  the  circulating  air  in  normal  condition. 

Theoretically,  the  system  which  would  maintain  ideal  air  condi- 
tions would  be  one  which  circulated  fresh,  pure,  conditioned  air,  at 
the  proper  temperature,  through  the  goods  in  ample  volume,  and 
discharged  it  after  one  passage  through  the  goods,  but  this  is  imprac- 
ticable, due  to  the  great  expense  of  purifying,  conditioning  and  cooling 
such  a  volume,  and  the  enormous  loss  occasioned  by  discarding  the 
air  at  such  a  temperature,  and  unnecessarily,  as  practically  the  con- 
ditions may  be  secured  in  another  manner,  that  is,  by  introducing  a 
small  amount,  comparatively,  of  pure  air,  which  will  rectify  the  air 
consumed  or  contaminated  by  the  goods. 


206  CORK  INSULATION 

Pure  air  is  difficult  to  secure,  especially  in  or  adjacent  to  thickly 
populated  communities  or  manufacturing  districts;  however,  various 
means  may  be  employed  to  assist  in  this  respect;  to  enter  into  dis- 
cussion of  this  subject  would  be  beside  the  point  at  this  time,  yet  it 
may  be  well  to  call  attention  to  one  agent,  which  has  been  utilized  to 
some  extent  and  found  beneficial  under  some  conditions,  but  due  to 
poor  design  or  mechanical  faults,  and  to  apparatus  not  adapted  to  use 
in  air  with  even  a  low  relative  humidity,  the  benefits  have  not  been 
secured  in  full  measure;  this  agent  is  "ozone"  or  "ionized  air."  Equip- 
ment for  the  production  of  ozone  is  now  perfected  and  being  installed 
under  a  guai'antee,  which  safeguards  the  purchaser. 

This  agent  and  the  equipment  for  producing  the  same  is  men- 
tioned here,  as  it  is  particularly  well  adapted  for  use  with  forced  air 
circulation,  and  gives  just  the  teeth  with  which  we  wish  to  endow 
our  air  in  order  to  make  it  function  as  a  purifier. 

In  consideration  of  all  that  has  been  brought  out  heretofore, 
there  is  but  one  conclusion  possible.  In  order  to  secure  proper  con- 
ditions for  the  preservation  of  food  products  there  must  be  correct 
temperature  and  air  conditions,  in  and  around  the  products,  which  can 
be  assured  in  one  way  only,  that  is,  by  mechanically  circulated  air. 

Air  conditions  can  only  be  secured  by  proper  humidity  control 
and  efficient  means  of  ventilating  or  rectifying,  or  both. 

96. — Preparation  of  Building  Surfaces  to  Receive  Insu'a- 
tion. — Perhaps  the  greatest  change  in  insulation  practice  dur- 
ing the  past  ten  years  has  occurred  in  connection  with  tlie 
method  of  applying  the  initial  course  of  insulation  to  Av.all 
surfaces,  especially  to  concrete,  hrick,  tile  or  stone. 

To  erect  corkboard  in  any  manner  against  plaster  over 
wood  or  over  metal  lath,  has  never  been  approved ;  such  lath 
and  plaster  must  be  removed  and  replaced  by  J^-inch  T.  &  G. 
sheathing  boards,  solidly  secured ;  and  whether  the  insulation 
of  a  cold  storage  room  should  be  erected  against  studs  closed 
in  by  sheathing,  wull  depend  entirely  upon  the  conditions  sur- 
rounding each  case.  The  dangers  from  confined  air  spaces 
back  of  insulation  ha.ve  already  been  pointed  out;  but  the 
purpose,  utility,  cost,  allowable  investment,  etc.,  should  be 
the  final  determining  factor  for  each  project. 

In  the  case  of  stone,  concrete,  brick  and  tile  surfaces  in 
existing  buildings,  it  is  necessary  to  take  such  surfaces  as 
they  come  along,  carefully  inspect  them,  and  then  properly 
prepare  them  to  receive  insulation.  Usually  such  surfaces 
have  been  whitewashed,  painted,  or  otherwise  coated ;  and  if 


STRUCTURAL  SUGGESTIONS  207 

so,  they  must  be  carefully  and  thoroughly  cleaned  before  it  is 
possible  to  apply  corkboard  insulation  to  them  successfully. 
Such  cleaning  must  usually  take  the  form  of  hacking,  which 
is  a  difficult  job  in  most  instances,  and  considerable  care  must 
be  exercised  if  the  finished  work  is  to  be  satisfactory. 

After  the  complete  area  of  such  walls  has  been  hacked,  or 
otherwise  prepared  as  required,  it  will  often  be  found  that 
their  surfaces  are  sufficiently  irregular  to  require  pointing 
up,  unless  the  first  kn^er  of  insulation  is  to  be  erected  in  a 
bedding  of  Portland  cement  mortar,  and  sometimes  even  then. 
On  the  other  hand,  if  the  purpose  of  the  insulated  room  or 
structure  makes  it  imperative  that  the  first  layer  of  insulation 
be  erected  in  hot  asphalt  to  walls  that  have  first  been  primed 
with  suitaljlc  asphaltic  material,  then  the  pointing  up  work 
must  take  the  form  of  a  complete  leveling  and  smoothing  up 
of  the  areas  to  be  insulated ;  because  the  thickness  of  the  hot 
asphalt  that  clings  to  the  sheets  of  corkboard  when  they  are 
dipped,  is  quite  insufficient  to  be  relied  upon  for  anything 
except  a  bond,  and  a  uniformly  full  bond  is  not  possible  except 
against  reasonably  smooth,  flat  surfaces.  Furthermore,  if  the 
primed  surface  to  which  the  sheets  of  corkboard  are  applied 
is  unexcn.  the  surface  of  the  finished  cork  work  will  be  just 
as  much,  or  possibly  more,  uneven,  and  may  seriously  inter- 
fere with  the  making  of  tight  insulation  joints  and  with  the 
proper  interior  room  finish  over  insulation,  not  to  mention 
the  air  pockets  behind  the  corkboards.  Consequently,  the 
cost  of  proper  preparation  for  insulation  to  be  applied  in 
existing  structures  and  following  the  most  approved  specifi- 
cations, is  sometimes  prohibitive,  and  an  insulation  specifica- 
•tion  less  expensive  must  be  selected  or  the  project  altered  or 
abandoned. 

The  preparation  of  surfaces  in  new  structures  to  receive 
insulation  frequently  does  not  have  the  forethought  and  atten- 
tion that  its  importance  justifies.  Preparation  should  begin 
with  the  drafting  of  the  plans  and  specifications  for  the  build- 
ing itself;  but  smooth,  even,  brick  walls  on  the  architect's 
drawings  are  not  necessarily  smooth,  even,  brick  walls  when 
actually  erected,  unless  thought  is  given  to  the  functioning 
of  those  walls  other  than  their  load-carrying  and  encompass- 


208  CORK  INSULATION 

ing  capacity.  It  costs  more  to  make  both  sides  of  a  building 
wall  equally  straight  and  smooth ;  but  if  the  latest,  approved 
insulation  specifications  are  to  be  carried  out,  this  point  must 
be  given  necessary  advance  attention. 

The  insulation  specification  usually  followed  for  many 
years  was  to  apply  the  first  layer  of  corkboard  to  the  new, 
clean  building  wall  in  a  bedding  of  Portland  cement,  then 
apply  the  second  layer  to  the  first  in  a  bedding  of  Portland 
cement,  or  in  hot,  odorless  asphalt,  and  then  finish  the  insula- 
tion off  with  Portland  cement  plaster,  applied  in  two  coats. 
Thus  surfaces  to  receive  insulation  had  to  be  only  reasonably 
smooth ;  but  failures  of  insulation  applied  in  this  way,  espe- 
cially in  ice  storage  houses,  became  sufficiently  numerous,  as 
the  years  passed,  to  finally  justify  active  investigation  of  the 
subject  by  manufacturers  and  important  users;  and  the  fail- 
ures of  insulation,  aside  from  those  due  to  poor  materials  and 
workmanship  at  the  time  of  installation,  were  traceable  to 
moisture  in  the  insulation,  which  collected  after  the  corkboard 
had  been  in  service  for  some  time  and  which  in  time  caused 
disintegration  of  the  corkboard  through  the  decomposition 
of  the  resin  binder  in  contact  with  water  or  which  caused 
more  rapid  disintegration  from  alternate  freezing  and  thawing 
of  moisture  in  the  insulation.  These  investigations  conclu- 
sively demonstrated  that  this  moisture  found  its  way  into 
the  cork  insulation  through  two  distinct  and  different  sources. 

When  water  is  precipitated  on  the  plastered  surface  of 
an  insulated  cold  storage  room,  by  the  condensation  of  moist- 
ure out  of  the  air  against  a  cool  surface,  a  part  of  such  water 
is  absorbed  by  the  plaster  by  capillarity,  which  tends  slowly 
to  disintegrate  the  plaster  while  placing  a  portion  of  this 
moisture  on  the  surface  of  the  insulation  directly  behind  the 
plaster.  The  cork,  unlike  other  materials,  will  not  take  up 
this  water  by  capillarity,  as  previously  explained,  but  such 
water  may  find  its  way  into  the  corkboards  by  gravity,  travel- 
ing through  small  interstices  or  voids  between  the  particles 
of  cork  bark  used  in  the  manufacture  of  the  corkboard.  While 
manufacturers  now  understand  and  appreciate  that  the  modern 
corkboard  product  of  maximum  worth  must  be  compact  and 
free  from  voids  to  the  greatest  possible  extent,  yet  it  would 


STRUCTURAL  SUGGESTIONS  209 

appear  that  in  the  manufacturing  process  all  voids,  especially 
surface  voids,  cannot  be  eliminated.  Thus  water  in  contact, 
as  just  explained,  has  been  knov^-n  to  penetrate  corkboard 
insulation  to  a  depth  of  an  inch  or  so  toward  the  outside 
building  M'alls. 

Water  may  also  find  its  way  into  corkboard  insulation 
through  an  entirely  different  source,  that  is,  from  the  outside 
of  the  building.  When  the  temperature  of  a  cold  storage 
room  is  lowered  by  refrigeration,  the  air  in  that  room  contracts 
with  cooling,  because  cold  air  occupies  less  space  than  the 
same  original  volume  of  warm  air.  Thus  the  cooling  of  the 
air  in  a  cold  storage  room  creates  in  that  room  a  temporary 
partial  vacuum,  or  an  unequal  pressure  between  the  inside 
and  the  outside  of  the  room.  If  the  room  is  tightly  closed, 
air  will  be  sucked  through  the  building  walls  and  the  insula- 
tion, to  balance  the  unequal  pressures,  and  this  air,  carrying 
with  it  water  in  suspension,  the  quantity  measurable  by  the 
humidity  of  the  air,  wuU  precipitate  its  moisture  in  the  insu- 
lated wall  where  the  dew  point  is  reached. 

The  discovery  of  these  two  distinct  ways  in  which  moist- 
ure is  placed  in  corkboard  insulation  has  been  of  great  value 
in  revising  insulation  specifications.  The  air-proofing  of  the 
surfaces  to  which  the  insulation  of  cold  storage  rooms  is 
applied,  to  be  carried  out  as  best  as  possible  under  each  set 
of  conditions,  is  now  done  wherever  possible  or  feasible,  so 
that  instead  of  air  being  drawn  through  the  building  walls 
and  the  insulation  to  compensate  a  partial  vacuum,  such  air 
will  be  supplied  through  some  other  channel  or  in  some  other 
way.  For  example,  it  is  now  frequently  the  practice  in  large 
ice  storage  houses  to  install  a  small  air  compensating  vent 
door  or  opening  in  or  near  the  ceiling. 

It  will  be  noted  that  surfaces  to  receive  insulation  are 
recommended  to  be  air-proofed,  not  water-proofed ;  and  the 
necessity  for  air-proofing  is  believed  to  increase  with  decrease 
of  cold  storage  room  operating  temperature,  and  in  a  general 
way  with  the  size  of  the  room,  that  is,  the  greater  the  cubical 
content  of  the  room  the  greater  will  be  the  vacuum  effect 
produced  by  the  refrigeration.  Again,  the  choice  of  the  kind 
of  materials  used  in  the  building  construction,  for  instance, 
will  decrease  or  increase  the  resistance  of  the  passage  of  air. 


210 


CORK  INSULATION 


A  hard,  repressed  brick  is  to  be  preferred.  If  monolithic 
concrete,  it  should  contain  a  so-called  water-proofing  material 
to  close  up  the  pores  as  much  as  possible  and  provide  just 
that  much  more  resistance  to  the  infiltration  of  air. 

Reasonably  smooth  and  level  inside  building  surfaces  must 
be  left  to  receive  insulation,  if  it  is  to  be  erected  in  hot  asphalt 
instead  of  the  usual  half-inch  bedding  of  Portland  cement  mor- 
tar ;  because  there  is  no  appreciable  thickness  to  hot  asphalt 


FIG.    70.— :\IILK    STORAGE    ROOM    WITH    CEILING    OF   IRGNED-ON-AT-THE- 
FACTORY  MASTIC  CORKBOARD  AND  WALL  INSULATION  PLASTERED. 


to  compensate  uneven  wall  surfaces,  as  previously  noted.  To] 
air-proof  building  walls,  two  good  coats  of  a  suitable  "asphalt 
primer" — not  ordinary  asphalt  paint — should  be  applied,  by 
brush  or  spray  gun,  as  reason  dictates.  A  suitable  priming  ma- 
terial is  a  good  grade  of  unfluxed  petroleum  asphalt  cut  to  the 
proper  consistency  with  a  solvent.  The  corkboards  should 
then  be  erected  in  hot,  odorless  asphalt  against  the  primed 
surface  of  the  building  walls,  and  the  second  course  of  insu- 
lation erected  to  the  first  in  the  same  material  and  addition-' 
ally  secured  with  hickory  skewers.  If  the  building  surfaces 
provided  in  the  first  place  are  not  reasonably  smooth,  the 
second  layer  of  insulation  may  have  to  be  erected  to  the  first 
layer  in  a  bedding  of  mortar,  instead  of  in  hot  asphalt,  to 


STRUCTURAL  SUGGESTIONS  211 

effect  a  general  leveling  up  of  the  last  course  of  insulation 
in  preperation  for  the  finish  over  insulation.  But  hot  asphalt 
between  the  layers  of  corkboard  is  preferable,  because  it  gives 
just  that  much  additional  air-proofing.  Detailed  information 
relative  to  asphalts  will  be  found  in  a  later  Article  in  this 
Chapter;  and  detailed  specifications  and  directions  for  apply- 
ing asphalts  will  be  found  in  their  proper  order  in  Chapters 
XIII  and  XIV,  respectively. 

It  must  not  be  inferred  that  the  greater  proportion  of 
moisture  in  corkboard  insulation  comes  in  from  the  outside 
through  the  building  construction.  It  is  but  one  of  two  ways, 
and  it  will  be  recalled  that  the  other  way  in  which  moisture 
finds  entrance  is  through  the  Portland  cement  plaster  finish 
that  it  has  been  for  so  many  yea^s  the  universal  custom  to 
apply ;  but  the  proper  preparation  of  building  surfaces  to 
receive  insulation  is  one  of  the  most  important  single  con- 
tributing items  to  the  high  efficiency  and  long  life  of  cold 
storage  room  insulation. 

97. — Insulation  of  Floors,  Columns,  Ceilings  and  Beams. — 

Probably  because  a  cold  storage  room  is  colder  at  the  floor 

than  at  the  ceiling,  even  though  the  floor  insulation  may  be 

wholly  inadequate,  some  have  been  tempted  to  specify  either 

very  light  floor  insulation,  or  none  at  all.     The  importance  of 

adequately   insulating   the   bottoms   of  ice-making  tanks   and 

!  the  floors  of  all  ice  storage  houses  and  cold  storage  rooms, 

.  especially  when  such  floors  are  located  on  the  ground,  is  prob- 

:  ably  not  as  fully  appreciated  as  is  the  necessity   for  proper 

insulation  of  other  surfaces. 

The  fact  that  a  cold  storage  room  is  colder  at  the  floor 
:-than  at  other  vertical  points,  even  though  it  has  no  insulation 
on  the  floor,  is  due  to  the  weight  of  cold  air  as  compared  with 
warm  air,  rather  than  to  the  possibility  of  the  heat  leakage 
being  less  through  such  uninsulated  floor  than  it  is  through 
the  insulated  walls  and  ceiling.  This  fact,  of  course,  is  very 
elemental ;  but  it  evidently  persists  in  the  minds  of  some,  and 
should  be  disposed  of  before  proceeding  to  the  consideration 
of  the  proper  insulation  of  all  floors  that  rest  on  the  ground. 
The  average  temperature  of  the  earth  varies  for  different 
years  and  localities  between  about  50°  and  60°  F.     If  a  cold 


212  CORK  INSULATION 

storage  room  is  operated  throughout  the  year,  the  loss  of 
refrigeration  per  unit  area  through  an  uninsulated  floor  resting 
on  the  ground  is  surprising;  and  if  such  room  is  operated 
during  the  warm  and  hot  seasons  only,  when  the  average  tem- 
perature of  the  earth  for  such  period  is  somewhat  higher  than 
the  average  for  the  year,  then  the  loss  of  refrigeration  through 
such  uninsulated  floor  in  contact  with  the  ground  is  even  a 
more  serious  item.  Where  temperatures  below  freezing  are 
maintained,  failure  to  adequately  insulate  ground  floors  is 
quite  likely  to  entail  serious  losses  other  than  those  of  unnec- 
essary heat  leakage,  as  the  freezing  of  the  earth  has  been 
known  to  disturb  entire  building  structures  with  consequent 
heavy  loss  to  property  and  business. 

The  insulation  of  floors  should  have  the  same  careful  con- 
sideration as  would  be  given  to  the  insulation  of  any  other 
building  surface.  Sharp  freezer  rooms  in  cold  storage  plants 
should  always  be  located  on  the  top  floor,  or  floors,  not  in 
the  basement,  and  not  between  floors  that  are  to  operate  at 
higher  cold  storage  temperatures.  If  sharp  freezers  are  lo- 
cated in  the  basement,  there  is  unnecessary  risk  of  the  freez- 
ing of  the  ground  underneath,  even  though  the  floor  is  heavily 
insulated,  with  consequent  heavy  losses;  and  if  they  are 
located  between  floors  that  are  to  operate  at  higher  tempera- 
tures, goods  stored  on  the  floor  directly  above,  even  though 
the  building  slab  between  is  well  insulated,  are  likely  to 
freeze. 

The  complete  arrangement  of  cold  storage  rooms — their 
size,  height,  location,  purpose,  and  general  utility — should  be 
most  carefully  thought  out  in  advance,  with  the  idea  of  ade- 
quate safeguard  and  maximum  economy  in  construction  and 
operation;  and  the  degree  of  success  obtainable  with  cold 
storage  rooms  is  directly  dependent  on  the  degree  of  intelli- 
gence and  care  that  is  put  into  such  planning. 

Columns  and  pilasters,  of  concrete  or  steel,  especially  those 
in  cold  storage  rooms  situated  in  basements  and  lower  floors, 
must  be  adequately  insulated,  primarily  as  a  safeguard  against 
disastrous  results  to  the  stability  of  the  entire  building  struc- 
ture caused  by  the  freezing  of  the  earth  at  their  base.  The 
proper  insulation  of  columns  and  pilasters  for  the  prevention 


STRUCTURAL  SUGGESTIONS 


215 


the  ceiling  construction,  as  floor  insulation,  and  the  insulation 
of  the  walls  can  be  made  continuous,  without  breaks  at  floor 
(ceiling)  levels,  by  providing  an  interior  building  structure  of 
concrete  and  steel  to  carry  the  load  of  the  cold  storage  section 
of  the  building  and  its  contents,  and  casing  it  in  with  self- 
sustaining  curtain  walls,  of  brick  or  concrete,  entirely  inde- 
pendent of  the  interior  structure  except  for  a  few  small  metal 
tic'^.  The  insulation  of  outside  building  walls  is  then  applied 
against  the  inner  surface  of  the  curtain  walls  in  a  continuous 
sheet,  without  breaks  at  floor  lines  and  connecting  with  the 


FIG.    73.— DETAILS   OF   BROKEN   WALL   INSULATION   WITH    3-FOOT  CORK- 
BOARD    RETURN    ON    CEILING    BELOW    (SEE    TEXT). 

proper  floor  (ceiling)  insulation  Mdierever  it  may  occur;  but 
where  insulated  interior  dividing  walls  are  required,  such  as 
those  walls  that  may  divide  the  cold  storage  section  of  the 
building  from  the  dry  storage  section,  provision  frequently 
need  be  made  only  for  self-sustaining  cork  walls  unsupported 
•by  interior  building  walls  of  any  kind.  In  this  way  the  cold 
storage  section  of  the  building  is  literally  enveloped  wdth  insu- 
lation, loss  of  refrigeration  is  reduced  to  a  minimum,  and  all 
ceiling  insulation  disappears  in  favor  of  floor  or  roof  insulation 
next  abo\'e. 

In  old  buildings  of  mill  construction,  it  is  frequently  pos- 
sible, and  if  so,  highly  desirable,  to  remove  the  ceiling  and 
floor  coverings  at  all  wall  lines  where  insulation  will  occur, 
and  make  such  insulation  continuous  through  and  between  the 


216  CORK  INSULATION 

joists  of  such  ceiling  and  join  it  with  floor  (ceiling)  insulation 
above.  In  old  buildings  containing  concrete  ceiling  slabs  so 
supported  as  to  make  cutting  through  for  continuous  insula- 
tion impossible  or  not  feasible,  the  wall  insulation  is  some- 
times carried  out  on  the  underside  of  ceiling  a  distance  of  3 
feet  and  then  the  entire  floor  area  above  is  insulated. 

The  effect  of  this  is  to  obtain  an  insulating  value  at  the 
uninsulated  perimeter  of  the  concrete  slab  of  something  in 
excess  of  36  inches  of  concrete,  which  will  suffice  for  normal 
temperatures,  and  places  much  the  greater  part  of  the  ceiling 
insulation  on  the  floor  above. 

In  old  buildings  of  such  design  that  continuous  insulation 
is  not  possible  or  feasible,  then  the  insulation  must  be  applied 
to  the  underside  of  wood  sheathed  joists,  or  to  the  under- 
side of  concrete  slab  and  around  all  beams  and  girders.  Great 
care  should  then  be  taken  to  properly  prepare  the  surfaces 
for  such  insulation,  to  properly  apply  it,  and  then  finally  to 
finish  such  insulation  off  in  accordance  with  the  most  approved 
modern  practice.  Especial  care  should  be  taken  to  carry  the 
insulation  around  all  beams  and  girders,  it  never  being  per- 
missible to  construct  any  kind  of  false  ceiling  at  the  bottom 
line  of  beams  or  girders  and  apply  insulation  to  such  false 
work,  leaving  closed  air  spaces  above,  because  such  spaces 
will  fill  with  water  and  the  insulation  will  fail.  If  the  height 
between  floors  of  the  building  is  greater  than  required  for  the 
cold  storage  rooms,  then  false  ceilings  hung  from  above  are 
permissable  if  they  leave  enough  space  between  for  good 
ventilation.  For  rooms  of  moderate  width,  under  the  sarr>e 
conditions,  where  there  will  never  be  extra  weight  applied  on 
top  of  the  cold  storage  room  ceiling  construction,  T-irons  are 
frequently  supported  on  the  side  wall  insulation,  12  inches 
apart,  to  support  two  layers  of  corkboard,  one  above  and  one 
below,  to  form  a  self-supporting  cork  ceiling  of  satisfactory 
utility. 

98. — Doors  and  Windows. — The  three  principal  heat  losses 
that  occur  in  the  average  cold  storage  room,  after  it  has  been 
brought  to  temperature,  are : 

(a)  Heat  leakage  through  the  insulated  floor,  walls  and  ceiling. 


I 


STRUCTURAL  SUGGESTIONS 


217 


(b)  Heat   entrance   permitted  by   the   opening   of   doors,   allowing 
warm  air  to  pass  in  and  cold  air  to  pass  out. 

(c)  Heat    brought    into    the    room    in    goods    placed    in    storage, 
through  the  medium  of  the  thermal  capacity  of  such   goods. 

The  relation  of  these,  or  the  importance  of  any  one  with 
respect  to  another,  in  the  case  of  any  given  cold  storage  room, 
is  dependent  on  too  many  variables  to  permit  of  comparisons; 
but  it  is  now  generally  recognized  that  the  modern  cold  stor- 
age door  plays  an  important  part  in  reducing  "door  losses" 


FIG.  74.— VICTOR  STANDARD  INSULATED  FRONT  FOR  CORKAND-CEMENT 
SERVICE  REFRIGERATORS. 


!  to  a  very  low  point.     The  fact  is  that  the  use  of  special  door 
■Equipment,  consisting  of  door  and  frame  and  hardware  assem- 
bled complete,  and  built  by  reliable  manufacturers,  for  cold 
stores,  is  now   so  universal  in   the   United   States   as   to   be 
standard,  the  time-honored,  ill-fitting,  home-made  cold  storage 
:  door  having  been  completely  discarded  in  favor  of  the  modern 
cold  storage  door  that  is  well  braced  and  heavily  constructed 
p  of  seasoned  lumber  to  withstand  years  of  hard  special  service, 
I  corkboard-insulated  for  highest  permanent  thermal  efficiency, 


218 


CORK  INSULATION 


and  delicately  fitted  to  heavy  frame  on  special  and  reliable 
hardware  for  quick  and  easy  opening  and  air-tight  closing. 
Cold  storage  windows,  except  for  retail  display  purposes,  were 
also  discarded,  following  the  advent  of  modern  electric  light- 
ing equipment.  Where  windows  must  be  used,  they  should 
be  specially  manufactured,  with  multiple  panes  and  sealed 
air  spaces  and  equipped  with  modern  improved  hardware. 

With  the  use  of  modern  cold  storage  door  equipment,  the 
entrance  of  heat  permitted  by  the  opening  of  doors  cannot  be 
further  reduced  except  through  the  employment  of  such  de- 


FIG.  75.— STEVENSON  "CAN'T  STAND  OPEN"  TRACK  DOOR—RIGHT  HAND 
SWING. 


vices  as  anterooms,  vestibule  or  "flapper"  doors,  automatic 
door  closers,  etc.,  which  will  reduce  the  amount  of  warm  air 
that  would  otherwise  enter  the  cold  room. 

Cold  storage  doors  may  swing  either  "right-hand"  or  "left- 
hand";  and  since  there  is  often  confusion  as  to  the  exact 
meaning  of  these  terms,  an  explanation  shall  be  given.  When 
standing  so  as  to  squarely  face  the  front  of  a  cold  storage 
door,  a  right-hand  door  will  have  the  hinges  on  the  right  hand 
side,  and  when  opened  with  the  right  hand  will  swing  past  the 
right  hand  side  of  the  body;  and  a  left-hand  door  will  have  the 
hinges  on  the  left  side  and  when  opened  with  the  left  hand 
will  swing  past  the  left  hand  side  of  the  body.  Cold  storage 
doors  may  have  any  one  of  three  kinds  of  sills;  namely,  (1) 
beveled  or  threshold  or  beveled  threshold,   (2)   high  or  over- 


STRUCTURAL  SUGGESTIONS 


219 


lapping,  and  (3)  no-sill  or  angle-iron  or  concrete.     Specifica- 
tions for  cold  stora.ce  doors  to  be  equipped  with  automatic 


FIG.    76.— JAMISON    STAN  J 


-LEFT   HAND    SWING 


trap    door    to    accommodate    overhead    track,    must    include    the 
height  of  the  fop  edge  of  track  above  the  finished  floor  of  the 


7IG.  77.— TYPES  OF  SILLS  FOR  COLD  STORAGE  DOORS— (LEFT)  BEVELED 
THRESHOLD;    (CENTER)    NO-SILL;   (RIGHT)   HIGH   SILL. 

■com  just  inside  doonvay,  and  the  depth  of  rail.       (Allowance 
Js  provided  by  manufacturers  for  any  bevel  of  sill  and  any 


220  CORK  INSULATION 

slight  variation  in  the  height  of  track  rail.)  The  width  and 
height  of  cold  storage  doors  are  always  specified  as  "the 
dimensions  inside  of  frame"  or  "door  in  the  clear."  In  the 
case  of  the  no-sill  type,  the  height  of  the  "door  in  the  clear" 
is  understood  to  be  the  dimension  measured  from  the  lowest 
point  of  frame  at  top  of  door  to  the  concrete  floor  level  in 
doorway.  (Consult  manufacturers  for  detailed  cold  storage 
door  specifications.) 

99. — Interior  Finishes  for  Cold  Storage  Rooms. — It  has 
been  noted  that  when  water  is  precipitated  on  the  plastered 
surface  of  an  insulated  cold  storage  room,  by  the  condensa- 
tion of  moisture  from  the  air  upon  a  cool  surface,  a  part  of 
such  water  is  absorbed  by  the  plaster  by  capillarity,  which 
slowly  disintegrates  the  plaster  while  placing  a  portion  of 
such  moisture  on  the  surface  of  the  insulation  directly  behind 
the  plaster.  Cork,  unlike  other  materials,  will  not  take  up 
this  water  by  capillarity,  but  such  water  may  by  gravity  find 
its  way  into  the  corkboards  through  possible  small  interstices 
or  voids  between  the  particles  of  cork  bark  that  comprise  tlie 
sheet  of  insulation. 

It  has  also  been  noted  that  the  modern  corkboard  product 
of  maximum  worth  must  be  compact  and  free  from  voids  to 
the  greatest  possible  extent,  although  the  nature  of  the  raw 
material,  and  the  manufacturing  process  that  must  be  fol- 
lowed, do  not  permit  of  the  elimination  of  all  voids,  especially 
surface  voids.  Water  in  contact  with  corkboard  on  the  walls 
of  buildings  can  be  expected  to  penetrate  the  insulation  to 
some  extent  at  least,  such  penetration  having  been  known  in 
extreme  cases  to  reach  a  depth  of  as  much  as  an  inch  or  so. 

Thus  it  should  be  evident  that  the  finish  over  the  cOi'-- 
board  insulation  on  cold  storage  room  walls  should  have  more 
than  passing  attention,  but  the  subject  has  long  been  neg- 
lected and  not  until  comparatively  recently  has  it  had  serious 
attention. 

Portland  cement  plaster  troweled  smooth  and  hard  for  the 
finish  coat  over  the  last  layer  of  insulation  is  much  better 
than  plaster  floated  ;  because  the  troweled  plaster  is  less  porous 
and  possesses  less  capillarity.  This  fact  does  not  seem  to  be 
appreciated  by  many,  however,  for  plaster  floated  has  long 


STRUCTURAL  SUGGESTIONS 


221 


been  the  universal  practice,  although  for  many  years  the 
United  States  Government  has  not  permited  floated  plaster  in 
government-inspected  meat  rooms  because  of  its  porosity  and 
consequent  tendency  to  take  up  water  and  become  foul. 

Materials  not  possessing  capillarity,  for  the  finish  coat 
over  cold  storage  room  insulation,  are  coming  into  much  favor. 
Factory  ironed-on  mastic  finish  coated  corkboards  for  the  sec- 


FIG.    78.— CORKBOARD    INSULATED    ICE    STORAGE    HOUSE    WITH    PORT- 
LAND   CEMENT    PLASTER    FINISH. 


ond  course,  with  all  joints  effectively  sealed  at  point  of  erec- 
tion with  the  point  of  a  hot  tool,  are  much  better  where  mois- 
ture is  encountered  in  cold  storage  rooms  than  is  any  kind  of 
plaster;  while  a  finish  having  an  emulsified  asphalt  base,  which 
may  be  troweled  on  at  the  job,  in  two  coats,  in  much  the  same 
way  as  plaster,  is  gaining  in  use,  although  it  has  probably  not 
yet  been  tried  over  a  sufficient  period  of  time,  and  its  formula 
has  not  yet  been  sufficiently  standardized,  to  permit  of  an 
unqualified  general  approval. 

If  good  troweled  plaster  on  walls  is  finished  off  first  with  a 


222  CORK  INSULATION 

filler  and  then  with  a  good  elastic  enamel,  such  surface  will 
present  an  efficient  barrier  to  the  entrance  of  moisture.  An 
elastic  enamel  is  required,  to  withstand  the  contraction  and 
expansion  of  the  room  surfaces  due  to  changes  in  temperature. 
The  Portland  cement  plaster,  however,  is  of  such  nature  as 
to  expand  and  contract  a  considerable  amount,  under  cold 
storage  room  conditions,  so  much  so  that  it  has  long  been 
the  practice  to  score  the  surface  of  such  plaster  finish  in  four 
foot  squares  to  confine  the  checking  and  cracking  to  such 
score  marks,  or,  if  you  wish,  to  provide  expansion  joints, 
similar  to  the  expansion  joints  in  concrete  sidewalks.  The 
weak  points  in  enameled  troweled  plaster  are  these  score 
marks,  or  expansion  joints,  and  especial  care  must  be  taken 
to  keep  all  such  cracks  so  well  closed  with  filler  and  enamel 
that  little,  if  any,  moisture  will  contact  with  the  insulation 
through  that  source.  To  do  this  is  not  as  difficult  as  it  may 
sound,  or  as  some  would  have  us  believe;  for  it  is,  in  many 
cold  storage  rooms,  entirely  feasible  and  practical  to  use 
enameled  troweled  plaster  on  walls  with  entire  success,  and 
if  to  the  plaster  mix  a  small  portion  of  some  good  and  suitable 
integral  waterproofing  compound  is  added,  the  value  of  the 
plaster  as  a  protective  coating  will  be  enhanced. 

The  service  in  cold  storage  rooms  of  cold  storage  buildings 
is  not  usually  as  severe,  from  the  standpoint  of  moisture,  as  is 
the  service  in  daily  ice  storages,  milk  rooms,  poultry  chill 
rooms,  and  a  host  of  small  cold  storage  rooms  in  small  plants ; 
because  in  cold  storage  buildings  the  rooms  are  not,  as  a 
rule,  entered  nearly  as  often  as  are  the  cold  storage  rooms  in 
small  plants,  and  when  the  rooms  in  a  cold  storage  building 
are  entered  it  is  invariably  through  anterooms  that  keep 
the  warm,  outside  air  from  rushing  directly  into  the  cold 
storage  room  and  precipitating  its  moisture  upon  cool  sur- 
faces of  every  kind.  Consec^uently,  the  need  for  the  most 
efficient  protective  finish  for  the  interior  of  cold  storage  rooms 
will  be  in  rooms  operating  at  moderate  temperatures,  such  as 
from  28°  to  35°  or  40°  F.,  in  which  rooms  the  moisture  pre- 
cipitated upon  cold  surfaces  is  not  converted  into  frost 
crystals,  or  not  so  quickly  converted  but  that  there  is  an  op- 
portunity for  some  of  it  to  be  absorbed. 


STRUCTURAL  SUGGESTIONS  223 

If  insulation  is  applied  to  the  underside  of  ceilings  in  rooms 
where  the  height  is  limited  and  cooling  coils  are  either  hung 
near  the  ceiling  or  placed  close  to  the  ceiling  in  bunkers,  as  is 
usual  in  the  small  cold  storage  rooms  to  be  found  outside  of 
cold  storage  buildings,  the  finish  over  the  corkboards  should 
always  be  something  more  vulnerable  than  plaster.  Either 
factory  ironed-on  mastic  finish,  with  all  joints  carefully  sealed 
upon  application,  or  the  very  best  emulsified  asphalt  prepara- 


FIG.    79.— BARUES    METAL    FLOOR    GRIDS. 

tion,  troweled  on  in  two  coats,  should  be  used  on  all  such 
insulated  ceiling  areas ;  and  where  coil  bunkers  are  used,  such 
special  asphaltic  waterproof  finish  should  also  be  used  on  all 
walls  down  at  least  to  the  lower  line  of  bunker  construction, 
and  often  preferably  on  the  entire  wall  areas  of  the  room. 
(Plaster  should  never  be  applied  in  rooms  to  be  used  for  the 
storage  or  handling  of  ice.) 

Wall  finishes  containing  asphalt  will  discolor  most  paints 
of  lighter  color  unless  a  continuous  coating  of  orange  shellac 
is  first  applied  to  the  asphaltic  surface,  but  aluminum  paint 
can  be  applied  directly  over  asphalt  without  fear  of  discolora- 
tion.    Aluminum  painted  surfaces  have  the  advantage  of  radi- 


224  CORK  INSULATION 

ating  less  heat  than  non-metallic  surfaces,  although  since  not 
over  10  per  cent  of  all  heat  normally  entering  an  insulated 
cold  storage  room  through  its  surfaces  is  traceable  to  radiation 
and  convection  combined,  the  insulating  effect  of  the  alumi- 
num paint  is  of  negligible  importance,  and  the  finish  should 
be  valued  alone  for  its  utility  as  a  coating  and  preserving 
material. 

On  floors,  it  is  customary  and  very  satisfactory  to  use  con- 
crete over  insulation,  such  concrete  troweled  hard  and  smooth 
and  sloped  to  drain.  In  ice  storage  houses  the  concrete  should 
be  of  increased  thickness,  or  contain  reinforcing  mesh,  or 
both,  on  account  of  the  weight  to  be  supported.  In  fur  stor- 
ages, the  desire  is  often  for  a  wood  floor  of  maple,  which  is 
satisfactory  in  dry  rooms  if  properly  laid.  In  milk  rooms, 
and  generally  wherever  metal  containers  must  be  moved  over 
floors,  metal  grids  should  be  imbedded  flush  in  the  concrete ; 
in  fact  the  use  of  such  metal  grids  is  increasing  rapidly  in 
cold  storage  rooms  of  every  kind. 

Lumber  in  cold  storage  rooms,  as  exposed  ceiling  con- 
struction where  insulation  is  applied  above,  or  as  bunker  con- 
struction, or  as  spacing  strips  on  the  floors  and  walls  of  ice 
storage  houses,  or  as  bumper  plates  around  the  walls  to 
protect  the  finish  from  boxes  and  barrels,  should  not  be  creo- 
soted  before  installation,  because  of  the  danger  from  odors, 
but  should  be  properly  painted  immediately  afterwards  and 
before  the  cold  storage  room  is  put  in  service. 

100. — Asphalt  Cement  and  Asphalt  Primer. — Authentic 
evidence  exists  that  asphalt  was  known  for  its  useful  and 
valuable  properties  almost  as  far  back  as  our  knowledge  of 
civilization  extends.  The  earliest  recorded  use  of  asphalt 
was  by  the  Sumarians,  inhabitants  of  the  Euphrates  Valley 
before  the  ascendency  of  the  Babylonians.  Unearthed  relics 
demonstrate  that  as  early  as  3000  B.  C,  asphalt  was  used  by 
these  people  as  a  cement  for  attaching  ornaments  to  sculp- 
tures, carvings  and  pottery.  An  asphalt  mastic  cast  exca- 
vated at  Lagash,  near  the  mouth  of  the  Euphrates,  dates  back 
to  2850  B.  C,  and  as  early  as  2500  B.  C.  the  Egyptians  utilized 
melted  asphalt  as  a  preservative  coating  for  the  cloth  wrap- 
pings of  their  mummies. 


!. 


STRUCTURAL  SUGGESTIONS  225 

The  famous  towers  of  Babylon  were  protected  for  some 
twelve  stories  with  a  coating  consisting  of  crushed  brick 
mixed  with  bitumen,  to  effectually  retard  the  encroachments 
of  both  damp  creeping  up  from  the  earth  and  of  the  flood 
waters  of  the  Euphrates.  Arthur  Danby  says  that  there 
is  no  doubt  but  that  the  sole  reason  why  the  remaining  tower 
of  Babylon  (Birs  Nimrod)  has  stood  for  such  a  great  length 
of  time,  is  that  the  builders  used  bitumen  as  an  admixture  in 
its  construction.  Nebuchadnezzar's  father,  as  king  of  Baby- 
lon, about  500  B.  C,  is  believed  to  have  first  used  asphalt  as 
a  mortar  for  brick  pavements,  and  Nebuchadnezzar  continued 
the  practice,  as  recorded  by  an  inscription  on  a  brick  taken 
from  one  of  the  streets. 

Thus  asphalt,  instead  of  being  a  product  of  modern  use, 
as  may  be  commonly  supposed,  has  a  useful  record  behind  it 
of  thousands  of  years,  handed  down  from  the  oldest  civiliza- 
tion; but  prior  to  about  1900  A.  D.  the  term  asphalt  was 
restricted  almost  exclusively  to  certain  semi-solid  or  solid 
bitumens  found  in  natural  deposits,  often  mixed  with  silt  or 
clay  and  thus  known  as  asphaltic-sand  or  rock-asphalt.  Trini- 
dad natural  asphalt  since  about  1880,  and  Bermudez  Lake 
natural  asphalt  since  about  1890,  have  been  imported  into  the 
United  States  and  used  for  paving  purposes.  Deposits  of 
asphaltic  sands  and  rock  asphalt  have  been  found  in  the 
United  States,  but  they  appear  to  be  somewhat  unsuited  for 
present  industrial  purposes.  Small  deposits  of  hard  and  nearly 
pure  asphalts,  commonly  known  as  Gilsanite,  Grahamite,  and 
so  forth,  have  also  been  discovered  in  the  United  States  and 
are  well  suited  for  the  manufacture  of  certain  asphalt  special- 
ties. 

Practically  all  natural  or  native  asphalt  is  too  hard  for 
direct  use  in  the  manufacture  of  asphalt  products;  and  after 
a  simple  refining  process,  which  consists  in  heating  the  crude 
material  until  water,  gas  and  other  volatile  material  is  driven 
off,  native  asphalt  must  be  softened  to  suitable  consistency  by 
combining  it  with  the  proper  amount  of  a  residual  petroleum 
known  as  flux  oil.  Petroleum  probably  always  served  as  an 
important  integral  part  of  all  asphalt  used  for  industrial  pur- 
poses; in  fact,  it  is  now  generally  believed  that  all  natural 
asphalt  originated  in  petroleum. 


226 


CORK  INSULATION 


The  first  petroleum  known  and  used  in  the  United  States 
was  of  the  paraffin  type  and*  occurred  in  Pennsylvania,  Ohio 
and  Indiana.  Distillation  of  this  petroleum,  to  remove  the 
more  volatile  matter,  yielded  a  thick,  greasy  oil  residue  which 
proved  quite  satisfactory  as  a  flux  for  natural  asphalt,  but 
which  upon  further  distillation  produced  coke;  whereas,  later, 
with  the  discovery  and  refining  of  California  petroleum,  fur- 


FIG.   80.— CORKBOARD   INSULATED  ICE   STORAGE   HOUSE   W^TH   IRONED- 
ON-AT-THE-FACTORY    MASTIC    FINISH. 


ther  distillation  of  California  residual  oil  produced,  before 
coke  was  formed,  a  semi-solid,  sticky  or  tacky  asphaltic 
material  resembling  native  asphalts.  Refinements  in  distilla- 
tion processes  improved  the  California  petroleum  asphalt  until 
it  was  demonstrated  that  if  recovered  by  suitable  means  it 
was  essentially  the  same  as  certain  native  asphalts. 

Appreciable    quantities   of   petroleum    asphalt   were    being 
used  in  the  United  States  for  paving,  by  about  1900.     How- 


STRUCTURAL  SUGGESTIONS  227 

ever,  it  was  received  on  trial  for  over  ten  years  until  experi- 
ence with  it  in  service  demonstrated  that  it  was  equally  as 
good  for  paving  purposes  as  the  natural  or  lake  asphalts.  By 
about  1911,  the  asphalt  produced  from  domestic  petroleum 
exceeded  the  Trinidad  and  Bermudez  asphalt  importations; 
and  since  then  the  production  of  petroleum  asphalt  has  con- 
tinued to  grow  rapidly,  stimulated  by  large  available  quanti- 
ties of  Mexican  petroleum  highly  asphaltic  in  character. 

Statistics  of  the  United  States  Geological  Survey  for  1919* 
show  the  following : 

UNITED  STATES   GEOLOGICAL   SURVEV   STATISTICS   FOR   1919. 

Asphalt    from    domestic    petroleum 614,692  tons  41.4% 

Asphalt    from    Mexican    petroleum 674,876  tons  45.5% 

Domestic   native   asphalt    (bituminous   rock) 53,589   tons  3.6% 

Other    domestic    native    bituminous    substances 34,692   tons  2.3% 

Asphalt    imported    from    Trinidad    and    Tobago 51,062  tons  3.5% 

Asphalt    imported    from    Venezuela 47,309  tons  3.2% 

Other   imported   asphalts    including   bituminous    rock 7,277  tons  0.5% 


TOTAL   ASPHALT    1,483,497  tons   100.0% 

.\sphalt     exported     from     U.     S.t     40,208  tons       2.7% 


Approximate  consumption   of  asphalt   in    U.    S 1,443,289   tons     97.3% 

These  figures  indicate  that  approximately  87  per  cent  of 

all  asphalt  produced  by  or  imported  into  the  United  States 

that  year  was  obtained  from  the  distillation  of  petroleum,  and 

since  then  this  ratio  has  continued  to  increase  in  favor  of  the 

petroleum  asphalts. 

;        Asphalt  would  appear  to  be  the  oldest  waterproof  adhesive 

j  known   to  man  ;  and   since  the   manufacture  of  asphalt  from 

i'  petroleum  has  made  it  readily  available  in  almost  unlimited 

'  quantities,   it   has   been   adapted   to   a   great   many   industrial 

;  purposes,  of  which  the  paving  industry  leads  and  the  roofing 

j  industry  is  second,   consuming  together  some  85   or  90  per 

;  cent  of  the  entire  asphalt  output.     The  remainder  of  the  out- 

i  put  is  used  for  waterproofing,  flooring,  insulating,  and  some 

I'ksphalt  finds  its  w^ay  into  the  manufacture  of  rubber  goods, 

I  paints,  varnishes,  bituminous  putty,  emulsions,  sealing  com- 

I  pounds,  floor  coverings,  etc. 

'        As  the  general  term  "asphalt"  is  commonly  applied  to  a 
great  variety  of  asphalts  and  asphaltic  products,  the  asphalt 


•Asphalts  and  Related  Bitumens  in   1919,  by  R.   W.   Cottrell. 

Note — See  also  "Asphalt,"  by  Prevost  Hubbard,  in  "The  Mineral  Industry  during 
•1925,"   Volume   34,    McGraw-Hill   Book    Co. 

tThis  does  not  include  manufactures  of  asphalt  valued  at  approximately  one-half 
'  the  value  of  the  tonnage  of  asphalt  exported. 


228  CORK  INSULATION 

to  be  used  in  applying  cold  storage  insulation  shall  be  termed 
"Asphalt  cement"  and  should  be  carefully  selected  for  certain 
properties  and  characteristics  that  are  highly  desirable  where 
foodstuffs  are  stored  and  where  the  success  of  the  installation 
depends  to  a  marked  degree  on  the  permanent  air-proofing 
and  cementing  qualities  of  the  Asphalt  cement  selected.  These 
properties  are  substantially  as  follows : 

(a)  Purity. 

(b)  Durability. 

(c)  Flexibility. 

(d)  Adhesiveness. 

Tests  to  determine  the  presence  of  these  properties  are 
reflected  in  the  specifications  of  the  American  Concrete  Insti- 
tute, the  American  Society  for  Testing  Materials  and  the 
United  'States  Bureau  of  Standards,  which  specifications  are 
much  the  same;  and  by  the  aid  of  these  specifications,  sup- 
ported by  the  practical  knowledge  of  the  requirements  of  a 
suitable  asphalt  for  use  in  applying  cold  storage  insulation  to 
building  or  other  surfaces,  a  specification  has  been  prepared, 
as  follows : 

Specification  for  Asphalt  Cement  for  Cold  Storage  Insulation. 

Impurities. — The  Asphalt  cement  shall  contain  no  water,  decom- 
position products,  granular  particles,  or  other  impurities,  and  it  shall 
be  homogeneous.  (Ash  passing  the  200-mesh  screen  shall  not  be  cc»n- 
sidered  an  impurity;  but  if  greater  than  1  per  cent.,  corrections  in 
gross  weights  shall  be  made  to  allow  for  the  proper  percentage  of 
bitumen.) 

Specific  Gravity. — The  specific  gravity  of  the  Asphalt  cement  shall 
not  be  less  than  1.000  at  77°  F.  (25°  C). 

Fixed  Carbon. — The  fixed  carbon  in  the  Asphalt  cement  shall  not 
be  greater  than  18  per  cent. 

Sulphur. — The  sulphur  and  sulphur  compounds  in  the  Asphalt  ce- 
ment shall  not  be  greater  than  1^  per  cent.,  by  the  ash  free  basis  of 
determination. 

Solubility  in  Carbon  Bisulphide. — The  Asphalt  cement  shall  be  sol- 
uble to  the  extent  of  at  least  98  per  cent,  in  chemically  pure  carbon 
bisulphide   (CS2). 

Melting  Point. — The  melting  point  of  the  Asphalt  cement  shall  be 
greater  than  165°  F.  and  less  than  190°  F.,  by  the  Ring  and  Ball 
method. 

Flash  Point. — The  flash  point  of  the  Asphalt  cement  shall  be  not 
less  than  425°  F.  (218.3°  C),  by  the  Cleveland  Open  Cup  test. 


STRUCTURAL  SUGGESTIONS  229 

Penetration. — The  Asphalt  cement  shall  be  of  such  consistency  as 
to  show  a  penetration  of  more  than  15  when  tested  at  32°  F.  (0°  C.) 
and  less  than  70  when  tested  at  115°  F.  (46.1°  C).  (0.2  millimeter 
shall  be  added  for  each  1.0  per  cent,  of  ash,  to  give  the  true  pene- 
tration.) 

Volatilisation. — The  loss  by  volatilization  on  heating  of  the  As- 
phalt cement  shall  not  exceed  1  per  cent.,  the  penetration  after  heating 
shall  be  not  less  than  80  per  cent,  of  the  original  penetration,  and  the 
ductility  after  heating  shall  have  been  reduced  not  more  than  20  per 
cent. 

Ductility. — When  pulled  vertically  by  a  motor  at  a  uniform  rate 
of  5  cm.  per  minute  in  a  bath  of  water,  a  cylinder  of  Asphalt  cement 
1  cm.  in  diameter  at  a  temperature  of  77°  F.  (25°  C.)  shall  be  elon- 
gated not  less  than  15  cm.  before  breaking,  and  at  a  temperature  of 
40°  F.  (4.5°  C.)  shall  be  elongated  not  less  than  3  cm.  before  breaking. 

Outline  of  the  Purpose  of  Specifications  for  Asphalt  Cement 
for  Cold  Storage  Insulation. 

Impurities  are  a  measure  of  the  care  with  which  the  Asphalt  cement 
has  been  refined  and  handled.  Usually  the  presence  of  impurities  in 
'arge  quantities  indicates  a  poor  grade  of  asphalt.  Water  as  an  impur- 
ity would  act  as  a  diluent  and  would  cause  foaming  in  the  kettle.  Ash, 
3r  mineral  matter,  is  not  considered  an  impurity  if  it  is  a  natural  con- 
stituent of  the  Asphalt  cement,  but  the  cementing  value  must  be  fig- 
ured on  the  bitumen  alone. 

Specific  Grcznty  of  the  Asphalt  cement  should  be  over  1.000  be- 
cause Asphalt  cements  of  a  pentration  satisfactory  for  cold  storage 
insulation  work  always  have  a  specific  gravity  greater  than  1.000, 
whereas  paraffin  base  and  air-blown  products  frequently  have  a  spe- 
:ific  gravity  less  than  1.000. 

j  Fixed  Carbon  is  to  some  extent  a  measure  of  the  chemical  con- 
i;titution  of  an  Asphalt  cement,  and  is  largely  used  to  determine  the 
;ource  and  uniformity  of  an  asphalt.  Fixed  carbon  is  not  free  carbon, 
A^hich  latter  is  practically  absent  in  Asphalt  cement,  but  fixed  carbon 
ncludes  free  carbon. 

Sulphur  and  sulphur  compounds  are  ordinarily  the  cause  of  the 
odor  in  oils  and  asphalts,  particularly  upon  heating.  An  Asphalt 
i^ement  that  is  low  in  sulphur  compounds  is  necessary  for  cold  storage 
nsulation  work. 

Solubility  in  Carbon  Bisulphide  is  a  measure  of  the  purity  of  an 
A.sphalt  cement;  and  the  cementing  value,  other  things  being  equal,  is 
proportional  to  the  CS2  solubility.  Any  carbonaceous  material,  such 
IS  coal  tar  or  pitch,  is  detected  by  this  test. 

Melting  Point  is  a  measure  of  the  temperature  at  which  the  As- 
)halt  cement  will  flow  readily.  The  melting  point  desired  is  deter- 
nined  by  the  workability  of  the  Asphalt  cement  on  corkboards  when 
lipped,  and  should  have  a  melting  point  somewhat  higher  than  the 
lighest  temperature  to  which  it  will  be  subjected  in  place  with 
nsulation. 


230  CORK  INSULATION 

Flash  Point  is  a  measure  of  the  amount  of  volatile  hydrocarbons 
that  are  present  in  the  Asphalt  cement,  and  of  the  readiness  of  the 
asphalt  to  decompose  by  heat. 

Penetration  is  a  measure  of  the  consistency  of  the  Asphalt  cement. 
It  is  merely  a  quick,  convenient  test  for  checking  up  numerous  sam- 
ples. The  penetration  is  expressed  in  degrees,  and  1/10  m.m.  equals 
one  degree.  The  penetration  to  be  desired  will  depend  upon  the 
climate,  the  ductility  and  adhesiveness  of  the  Asphalt  cement. 

Loss  by  Volatilization  is  a  measure  of  the  amount  of  light  hydro- 
carbons that  are  present  in  Asphalt  cement,  v^rhich  indicates  its  ten- 
dency to  oxidize  and  to  lose  its  ductility  and  penetration. 

Ductility  is  a  measure  of  the  ability  of  an  Asphalt  cement  to  ex- 
pand and  contract  without  breaking  or  cracking.  The  same  asphalt 
at  a  higher  penetration  should  have  a  higher  ductility,  so  all  ductility 
tests  should  be  based  on  a  certain  definite  penetration  regardless  of 
temperature,  or  should  be  based  on  a  temperature  of  32°  F.  (0°  C). 
Ductility  is  also  a  measure  of  the  cementing  strength. 

Viscosity  is  a  measure  of  the  ability  of  the  Asphalt  cement  to  im- 
part plasticity  and  malleability. 

The  methods  of  testing  to  be  followed  in  connection  with 
Specification  for  Asphalt  Cement  for  Cold  Storage  Insulation,  are 
those  of  the  American  Society  for  Testing  Materials,  as 
follows: 

(a)  Determination    of    Bitumen    in    Asphalt    Pioducts    (Deducted 
from   100  per  cent,  equals  Purity)  A.  S.  T.  M.,  D4-23T. 

(b)  Softening    Point    of    Bituminous    Materials     (Ring    and    Ball 
Method)  A.  S.  T.  M.,  D36-24. 

(c)  Flash  and  Fire  Points  of  Bituminous  Materials   (by  the  Cleve- 
land Open  Cup  Method)   A.  S.  T.  M.,  D92-24. 

(d)  Penetration  of  Bituminous   Materials,  A.  S.  T.  M.,  D5-25 

(e)  Loss  on  Heating  of  Oil  and  Asphaltic  Compounds,  A.  S.  T.  M., 
D6-20. 

(f)  Ductility  of  Bituminous  Materials,  A.  S.  T.  M.,  D113-22T. 

(g)  Sulphur  in  Bituminous  Materials  (Ash  Free  Basis)  A.  S.  T.  M., 
D29-22T. 

The  Kansas  City  Testing  Laboratory,  in  its  Bulletin  No. 
15,  publishes  values  for  the  composition  of  natural  and  petro- 
leum asphalts,  as  follows : 

1.— COMPOSITION    OF  NATURAL  ASPHALTS. 


Natural 
Trinidad 

Ber- 

mudez 
94.0% 

2.0% 

1.085 
13.5% 
180 

2.5 

4.0% 

70'0% 
82.5% 
10.3% 
0.7% 

Gil- 

sonite 

99.4% 
0.5% 
1.045 

13.0% 
300 
0 

0.1% 
1.3% 

30.0% 

Gra- 
hamite 

56.0% 

94.1% 

Mineral     Matter     

36.8% 

1.400 

5.7% 
1.171 

.    1 1  0% 

53.3% 

Melting    Point,    °F 

Penetration    (77°    F  )             ... 

190 

...      05 

Cokes 
0 

6.0% 

0.2% 

6  5  % 

2.0% 

65.0% 

0.4% 

Total    Carbon    (ash    free)    

82.6% 

87.2% 

Hydrogen    (ash    free)    

Nitrogen    (ash    free)     

10.5% 

0.5% 

7.5% 
0.2% 

STRUCTURAL  SUGGESTIONS  231 

2.— COMPOSITION   OF   PETROLEUM   ASPHALTS. 

Mexi-  Mid-Continent       Calif-             Stano- 

can Air   Blown ornia  lind* 

Bitumen     99.5%  99.2%             99.5%             99.8% 

Mineral   Matter    0.3%  0.7%                0.3%                0.3% 

Specific    Gravity     1.040  0.990                1.045                1060 

Fixed     Carl  on     17.5%.  12.0%              15.0%               17.5% 

Melting    Point    °F 140  180  140  135 

Penetration    (77°    F.)    55  40                      60                      SO 

Free    Carbon     0.0  0.0                    0.0                    0.0 

Sulphur    (ash     frte    basis) 4.50%  0.60%               1.657o            0.35% 

Petroleum    Ether    Soluble    70.0%)  72.0%              67.0%,              70.0% 

Cementing  Properties good  poor                  good                gooa 

Ductility     (squarp     mold) 45  cm  2  cm                    70  cm  100  + 

Loss  at  32°   F.   5  hrs 0.2%,  0.1%               0.2%,               0.1% 

Heat  test adherent smooth adherent scaly 

These  values  were  obtained  by  methods  of  testing  as  pub- 
lished by  the  K.  C.  T.  L.,  Bulletin  No.  15,  which  are  in  many 
particulars  slightly  different  from  the  methods  adopted  by 
the  American  Society  for  Testing  Materials,  and  consequently 
the  values  of  the  K.  C.  T.  L.  are  given  here  for  general  infor- 
mation only  and  are  in  no  way  to  be  confused  with  the  values 
called  for  in  a  Specification  for  Asphalt  Cement  for  Cold  Storage 
Insulation,  or  with  an  Asphalt  Primer  for  Use  with  Asphalt 
Cement. 

The  "Heat  Test"  mentioned  in  the  K.  C.  T.  L,  Table  No.  2, 
should  be  of  interest,  as  follows : 

Resistance  of  Asphalt  Cement  to  Oxidation,  K,  C,  T.  L.,  1919 

A  strip  of  thin  sheet  iron  2  inches  wide  and  6  inches  long  is 
covered  on  its  lower  4  inches  with  the  melted  asphaltic  cement.  This 
strip  is  placed  in  an  oven  at  275°  F.  for  15  minutes  and  allowed  to 
thoroughly  drain. 

It  is  removed  from  the  oven  and  allowed  to  cool,  then  placed  in 
an  electrically  heated  oven  at  a  temperature  of  450°  F.  for  one  hour. 
'  At  the  end  of  the  hour,  the  door  of  the  oven  is  opened  and  the  heat 
is  turned  off,  the  specimen  being  allowed  to  remain  in  the  oven. 

The  oven  shall  be  one  having  outside  dimensions  of  12x12x12 
inches  with  an  opening  in  the  top  1  cm.  in  diameter,  the  heating  ele- 
ments being  in  the  bottom  of  the  oven.  The  resistance  shall  be  so 
distributed  that  the  heat  is  uniform  throughout  the  oven.  The  lower 
end  of  the  strip  shall  be  suspended  so  that  it  is  at  least  3  cm.  from 
;  the  bottom  of  the  oven. 

The  resistance  is  preferably  so  arranged  that  three  different  heats 
can  be  maintained  with  a  snap  switch  such  that  the  lowest  heat  is 
325°  F.,  the  medium  heat  is  400°  F.  and  the  highest  heat  is  450°  F. 

After  being  subjected  to  these  tests,  the  film  of  asphalt  should  be 
brilliant  and  lustrous,  should  not  be  scaly  and  fragile,  should  adhere 
fi  firmly  to  the  metal  and  should  not  be  dull  and  cheesy  in  texture. 

'(Cracked-pressure   tar   residue. ") 


232  CORK  INSULATION 

A   suitable   Asphalt  Primer   for   initial   application   to    con-    I 
Crete  and  masonry  surfaces  as  preparation  for  the  erection  of 
cold  storage  insulation  in  Asphalt  cement,  is  as  follows:  i 

Asphalt  Primer  for  Use  With  Asphalt  Cement  j 

The  asphalt  used  in  preparing  the  primer  shall  be  homogeneous    i 
and  free  from  water,  and  shall  conform  to  the  following  requirements:     ■ 

(a)  Melting  point  (R  &  B) 140  to  225°  F.  (60°  to  107.2°  C.)    I 

(b)  Penetration  at  77°  F.  (25°  C.)  100  grams  pressure  for  5 
seconds   20  to  50 

(c)  Flash  point   (Open  Cup).... Not  less  than  347°  F.   (175°  C.) 

(d)  Loss  on  heating  50  grams  at  325°  F.  (163°  C.)  for  5 
hours  Not  more  than  1% 

(e)  Penetration  at  77°  F.  (25°  C.)  100  grams  pressure  for  5 
seconds,  of  the  residue  after  heating  SO  grams  at  325'  F. 
(163°  C.)  for  5  hours  as  compared  with  penetration  of 
asphalt  before  heating  Not  less  than  60% 

(f)  Ductility  at  77°  F.  (25°  C.) Not  less  than  15  cm. 

(g)  Insolubles  in  Carbon  disulphide Not  more  than  2% 

The  solvent  used  in  cutting  the  asphalt  (in  preparing  the  primer) 
shall  be  a  hydrocarbon  distillate  having  an  end  point  on  distillation 
of  not  above  500°  F.  (250°  C),  of  which  not  more  than  20  per  cent 
shall  distill  under  248°  F.  (120°  C). 

The  finished  Asphalt  Primer  shall  be  free  from  water*  and  shall 
conform  to  the  following  requirements: 

(a)  Sediment*   Not  more  than  1% 

(b)  Asphaltic  base  by  weight 25  to  35% 

101. — Emulsified  Asphalt. — Emulsified  asphalt  and  emulsi- 
fied asphalt  plastic,  for  the  interior  finish  of  cold  storage 
rooms,  and  sometimes  for  the  priming  of  surfaces  in  prepara- 
tion for  insulation  to  be  applied  in  hot  Asphalt  cement,  has 
had  enough  publicity — favorable  and  unfavorable — to  justify 
a  very  careful  look  into  the  general  subject  of  asphalt  emul- 
sions. 

"Colloid  chemistry  is  the  chemistry  of  grains,  drops,  bub- 
bles, filaments,  and  films,"  according  to  Bancroft;  but  colloid 
chemistry  actually  deals  with  grains,  drops,  and  bubbles  only 
when  they  are  sufficiently  small,  of  diameters  ranging  from 
ICX)  millimicrons  to  1  milllmicronf,  and  when  such  particles 
are  surrounded  by,  or  dispersed  in,  some  other  substance,  as 
dust  in  air  (smoke),  water  in  butter,  oil  in  water  (milk),  air 


*To  test   for  Water  and  Sediment,   use  A.S.T.M.   Method  D9S-23T. 

tA  millimicron,  1  /jl/i.  is  one  niillicnth  of  a  millimeter,  100  fi/t  just  barely  being 
visilale  with  the  aid  ot  the  best  microscope,  and  the  largest  molecules  approach  a 
diameter  of  l  nf/i,, 


STRUCTURAL  SUGGESTIONS 


233 


in  water  (foam),  etc,  "The  colloidal  realm  ranges  from  the 
lower  limit  of  microscopic  visibility  to  the  upper  limit  of  mo- 
lecular dimensions,"  says  Holmes,  and  adds  that  most  colloidal 
particles  are  aggregates  of  hundreds  or  even  thousands  of 
molecules. 

Water,  wood,  paper,  clothing,  glass,  cement,  paints,  inks, 
asphalt,  cheese,  oils,  and  countless  other  materials  in  common 


FIG.    81.— INSULATED   ICE   STORAGE   HOUSE   WITH    PLASTIC   MASTIC 
FINISH    APPLIED    OVER    CORKBOARD   AT    POINT    OF    ERECTION. 

I  use  are  colloidal,  that  is,  may  be  dispersed  in  or  surrounded  by 
'  some  other  substance. 

A  small  quantity  of  oil  may,  for  example,  be  dispersed  in 
'Water,  by  vigorous  shaking  or  stirring;  but  to  maintain  the 
I  dispersion,  or  keep  the  emulsion,  is  the  problem.     Aside  from 
tl  the  unequal  specific  gravities  of  the  two  substances,  the  fact 
of  the   unequal  surface  tensions  of  water  and  oil   assists   in 
causing  the  microscopic  drops  of  oil  to  form  together,  separat- 
ing from  the  water,  the  surface  tension  of  any  given  liquid 
'  being  that  tension  by  virtue  of  which  it  acts  as  an  elastic 


234  CORK  INSULATION 

enveloping  membrane  tending  always  to  contract  the  surface 
of  the  liquid  to  the  minimum  exposed  area.*  When  a  sub- 
stance is  colloidally  dispersed,  the  efifect  of  gravity  is  con- 
siderably counteracted,  while  surface  tension,  electric  (ionic) 
charge,  and  other  forms  of  energy  increase  greatly. 

Thus  by  lowering  the  surface  tension  of  water,  by  the 
introduction  of  an  alkali,  an  oil-in-water  emulsion  should  keep 
longer.  But  water  molecules  are  always  in  constant  motion 
when  above  absolute  zero  temperature,  and  bombard  the  sus- 
pended colloids  of  oil  from  all  sides,  tending  to  move  them 
about,  and  thus  to  coagulate  or  unite  upon  touching  due  to 
the  surface  tension  of  oil.  Then,  too,  particles  in  the  col- 
loidal state  bearing  unlike  electric  charges,  tend  to  attract 
each  other,  and  thus  coagulate;  while  particles  similarly 
charged,  tend  to  repel,  and  thus  move  about,  and  coagulate 
upon  touching. 

It  will  be  seen  that  lowering  the  surface  tension  often 
exerts  considerable  influence  in  emulsification,  but  the  con- 
centration of  a  film  of  some  non-adhesive  gelatin  substance 
around  the  suspended  colloids,  so  that  they  have  difficulty  in 
touching,  is  usually  of  more  importance. 

There  are  several  methods  of  subdividing  common  sub- 
stances so  that  they  may  be  colloidally  suspended,  some  meth- 
ods being  purely  mechanical  and  others  chemical ;  but  in  con- 
nection with  proposed  chemical  methods,  it  must  be  remem- 
bered that  colloidal  suspensions  are  not  true  solutions,  colloid 
aggregates  often  being  thousands  of  times  as  large  as  a  mole- 
cule while  molecules  only  are  found  in  true  solutions. 

Colloid  particles  have  an  ability  to  adsorb  other  substances, 
that  is,  hold  other  substances  to  their  surfaces,  and  it  is  this 
property  that  makes  it  possible  to  coat  or  cover  such  colloids 
with  a  non-adhesive  substance,  such  as  starch  or  geletin  or 
clay,  so  that  the  colloids  will  not  coalesce  or  unite  when  they 
touch  each  other.  On  the  other  hand,  if  the  particles  in  sus- 
pension were  originally  of  too  great  size  to  fall  within  the 
range  of  the  colloidal  realm,  and  thus  are  beyond  the  help  of 


*A  cube  1  cm.  on  edge  has  a  surface  of  6  sq.  cm.  If  subdivided  in  much  smaller 
cubes  100  ////  on  edge,  the  total  surface  is  600,000  sq.  cm  If  further  subdivided  into 
the  colloidal  realm  of  cubes  10  /i/i  on  edge,  the  total  surface  is  6,000,000  sq.  cm.  Sur- 
face tension  tends  to  reduce  the  colloidal  particles  to  the  cube  1  cm.  on  edge,  or, 
more  properly,  to  a  sphere. 


STRUCTURAL  SUGGESTIONS  235 

the  bombardment  of  the  water  molecules  (Brownian  move- 
ment) to  keep  them  suspended,  such  aggregates  will  settle. 
Emulsoids  are  dehydrated  and  coagulated  by  excessive 
amounts  of  salts,  by  nitric  acid,  sometimes  by  heat  and  by 
shaking.  Thus  if  it  is  necessary  to  shake  an  emulsion  a  great 
deal,  in  handling,  or  shipping,  or  stirring  to  counteract  settling, 
the  particles  (having  lost  their  full  protective  coats  by  dis- 
turbance) may  coagulate  an  amount  sufficient  to  destroy  the 
emulsion. 

It  is  the  non-adhesive  substance  used  to  coat  the  dispersed 
colloidal  particles  that  is  known  as  the  emulsifying  agent, 
and  such  agent  must  be  capable  of  being  colloidally  dispersed 
also.  The  emulsifying  agent  selected,  however,  must  be  such 
that  the  adsorptive  power  of  its  colloids  is  less  than  that  of  the 
colloidall}^  dispersed  basic  substance  being  emulsified,  else  the 
dispersed  protective  colloids  of  the  emulsifying  agent  will  not 
be  held  to  the  surface  of  the  colloidal  particles  of  the  basic 
material,  but  the  reverse  will  occur,  and  the  colloidal  particles 
of  the  emulsifying  agent  will  become  coated  by  the  dispersed 
colloids  of  the  basic  material.  The  adsorptive  power  of  an 
adhesive  type  of  colloidal  particle,  for  colloidal  particles  of  a 
non-adhesive  and  protective  character,  is  apparently  increased 
by  the  simple  addition  of  a  flocculating  agent  that  will  tend 
to  coagulate  or  unite  the  protective  colloids  in  larger  aggre- 
gates about  the  basic  colloids  and  thus  give  the  basic  colloids 
a  certain  measure  of  greater  protection  or  isolation  one  from 
another. 

If  even  a  faint  conception  of  colloid  chemistry,  and  par- 
ticularly the  preparation  and  holding  of  emulsions,  is  possible 
from  the  foregoing  paragraphs,  then  a  consideration  of  the 
preparation,  handling,  shipping  and  application  of  asphalt 
emulsions  can  follow. 

Asphalt,  as  has  been  noted,  is  a  colloidal  substance;  it  is 
one  that  may  be  colloidally  dispersed  in  water  by  admixture 
of  the  molten  material  with  a  hot  aqueous  alkaline  solution  ; 
it  is  a  material  that  is  capable  of  being  mechanically  dispersed 
in  a  colloidal  state  in  water  that  has  had  its  high  surface 
tension  relieved.  But  to  emulsify  asphalt,  that  is,  hold  it  in 
colloidal  suspension,  requires  the  addition  of  a  suitable  emulsi- 


236  CORK  INSULATION 

fying  agent,  one  that  is  non-adhesive,  capable  of  colloidal  dis- 
persion and  of  inferior  adsorptive  power  in  the  presence  of  the 
basic  asphalt  colloids.  In  a  word,  the  colloids  of  the  emulsi- 
fying agent  must  be  such  as  to  be  held  to  the  surface  of  the 
dispersed  asphalt  colloids  in  sufficient  quantity  and  with  suf- 
ficient bond  to  prevent  the  colloidal  particles  of  asphalt  from 
sticking  together  as  they  touch  each  other  during  propulsion 
about  through  the  aqueous  alkaline  solution  by  the  forces 
that  make  colloidal  suspension  possible. 

U.  S.  Letters  Patent  No.  1,582,467,  for  example,  sets  forth 
as  one  of  its  claims  the  follow^ing: 

A  process  for  producing  an  aqueous  bituminous  emulsion 
which  consists  in  melting  solid  bitumen  of  the  type  arti- 
ficially prepared  from  petroleum,  adding  thereto  with  agita- 
tion a  proportion  less  than  10%  of  an  emulsifying  agent 
comprising  a  substance  of  the  starch-dextrin  type,  and  then 
separately  adding  a  dilute  aqueous  solution  of  alkali,  and 
maintaining  the  heating  and  agitation  of  the  mixture  until 
emulsification    has   been   efifected. 

U.  S.  Letters  Patent  No.  1,567,061  sets  forth  certain  claims 
relating  to  the  admixture  of  a  flocculating  agent*  to  an  asphalt 
emulsion  to  increase  the  degree  of  protection  to  the  suspended 
asphalt  colloids  by  causing  the  colloids  of  the  emulsifying 
agent  to  more  tenaciously  cling  to  the  suspended  colloidal 
asphalt,  as  follows : 

A  process  of  forming  a  non-adhesive  emulsion,  consisting 
in  emulsifying  an  adhesive  bituminous  substance  with  col- 
loidal clay  in  an  aqueous  vehicle,  adding  aluminum  sulphate 
to  the  emulsion  to  cause  the  emulsifying  particles  to  more 
tenaciously  gather  about  the  bituminous  substance. 

The  colloidal  dispersion  of  asphalt  in  water  is  usually 
accomplished  by  heating  the  asphalt  to  about  225°  F.  and 
adding  it  to  a  hot  aqueous  alkaline  solution  under  vigorous 
and  intimate  agitation ;  and  there  have  been  a  number  of 
patents  issued  covering  mechanical  equipment  for  many  ways 
of  accomplishing  such  dispersion.  It  would  therefore  appear 
that  the  equipment  used  and  the  care  exercised  in  the  manu- 
facturing process  may  have  considerable  to  do  with  the  worth 
of  the  finished  product.  For  instance,  if  the  asphalt  were  not 
actually  broken  up  into  microscopic  particles  sufficiently  small 
to  place  them  in  the  colloidal  realm,  then  the  tendency  of  that 

*Aromoni3  salts  arp  frequently  used  in  emulsions  as  flocculating  agents. 


STRUCTURAL  SUGGESTIONS  237 

"emulsion"  would  be  to  settle  in  the  container,  the  particles 
of  asphalt  simply  being  held  apart  by  their  coatings  of  non- 
adhesive  material ;  and  the  disturbances  of  handling,  shipping, 
and  stirring  to  counteract  settling  may  sufficiently  dislodge 
the  protective  coatings  from  the  asphalt  particles  to  cause 
enough  coagulation  to  make  the  emulsion  unfit  for  practical 
use.  The  use  of  an  unsuitable  emulsifying  agent,  or  incor- 
rect proportions  of  ingredients,  or  insufficient  heat,  or  other 
errors  of  omission  or  commission,  may  conceivably  be  respon- 
sible for  an  unsatisfactory  emulsified  asphalt  product. 

Back  of  it  all,  too,  is  this  important  fact :  If  a  good  grade 
of  a  suitable  asphalt  is  used  as  the  basic  material  to  be  emulsi- 
fied, then  vv^hen  dehydrated  on  the  w^alls  of  a  building,  or  on 
cork  insulation,  there  will  remain  the  same  good  grade  of  a 
suitable  asphalt  as  a  protective  coat;  otherwise,  not;  if  a  poor 
asphalt  is  emulsified,  it  remains  a  poor  asphalt,  always. 

Emulsified  asphalt  is,  of  course,  subject  to  freezing,  which 
is  a  serious  objection  to  the  shipping  and  handling  of  the 
material  in  cold  weather. 

The  exact  determination  of  the  constituents  of  an  asphalt 
emulsion  is  usually  attended  with  considerable  difficulty  and 
no  predetermined  scheme  can  be  made  applicable  to  all  mate- 
rials of  this  character.  The  following  methods,  how='ever,  are 
used  by  the  United  States  Office  of  Public  Roads  and  Rural 
Engineering,  according  to  Prevost  Hubbard,  and  have  yielded 
reasonably  satisfactory  and  fairly  accurate  results : 

Special  Tests  for  Emulsions. 

Fatty  and  Resin  Acids. — In  order  to  break  up  the  emulsion,  a  20- 
gram  sample  is  digested  on  a  steam  bath  with  100  cubic  centimeters 
of  N/2  alcoholic  potash.  The  digestion  is  carried  out  in  a  flask  with 
a  reflux  condenser  for  about  45  minutes.  The  solution  is  filtered 
and  the  precipitate  washed  with  95  per  cent  alcohol.  The  filtrate  is 
evaporated  to  dryness,  after  which  the  residue  is  taken  up  with  hot 
water  and  any  insoluble  matter  is  filtered  ofif.  The  aqueous  solution, 
which  contains  the  potassium  soaps  of  the  fatty  acids,  is  acidified 
with  dilute  sulphuric  acid  and  then  shaken  in  a  separatory  funnel 
with  petroleum  ether.  The  aqueous  portion  is  drawn  off  and  the 
ethereal  layer  shaken  up  with  cold  water  and  washed  twice,  after 
which  it  is  evaporated  in  a  weighed  platinum  or  porcelain  dish  to 
constant  weight,  first  over  a  steam  bath  and  then  in  a  drying  oven 


238  CORK  INSULATION 

at  105°  C.  The  residue  consists  of  the  fatty  and  resin  acids  present 
in  the  emulsion. 

Water. — The  percentage  of  water  in  the  emulsion  is  determined 
by  distilling  a  100-gram  sample  in  the  retort  used  for  dehydration. 
The  distillation  is  carried  out  in  exactly  the  same  manner  as  de- 
scribed under  this  test  until  the  volume  of  water  in  the  receiver  shows 
no  further  increase.  Any  oils  that  come  over  are  thoroughly  mixed 
with  the   material  remaining   in   the   retort. 

Aiiniionia. — Many  emulsions  contain  ammonia,  and  when  this  is 
present  a  second  distillation  of  the  material  is  necessary.  This  is 
carried  out  on  a  100-gram  sample  in  exactly  the  same  manner  as 
described  for  the  determination  of  water,  except  for  the  fact  that  40 
cubic  centimeters  of  a  10  per  cent,  solution  of  caustic  potash  is  added 
to  the  contents  of  the  retort  before  beginning  the  distillation.  The 
distillate  is  collected  in  a  measured  volume  of  N/2  sulphuric  acid. 
When  the  distillation  is  completed  the  excess  acid  is  titrated  with 
N/2   caustic   potash,   and   the   ammonia   thus   determined. 

Ash. — A  one-gram  sample  of  the  dehydrated  material  is  ignited  in 
a  weighed  platinum  or  porcelain  crucible.  The  ash  will  contain  any 
inorganic  matter  from  the  bitumen  as  well  as  the  fixed  alkali  present 
in  the  soap.  The  results  are,  of  course,  all  calculated  on  the  basis 
of  the   original  material. 

Total  Bitumen. — A  two-gram  sample  of  dehydrated  material  is 
extracted  with  carbon  disulphide  as  described  in  the  method  for  the 
determination  of  total  bitumen,  flask  method,  and  in  this  manner 
the  organic  matter  insoluble  in  carbon  disulphide  can  be  determined. 

Having  determined  all  constituents  as  above  noted,  it  is  assumed 
that  the  difiference  between  their  sum  and  100  per  cent,  is  bitumen, 
which    amount   is    reported    accordingly. 

It  will  be  seen  that  with  emulsified  asphalt,  as  with  many 
"prepared"  products,  the  average  purchaser  must  rely  on  the 
manufacturer  for  the  quality  and  fitness  of  the  emulsion  for  the 
work  in  hand. 

The  advantage  offered  by  a  suitable  emulsified  asi)halt  as 
a  priming  material  for  masonry  surfaces,  as  compared  with 
an  Asphalt  primer,  is  that  emulsified  asphalt  is  non-inflam- 
mable ;  and  the  advantage  of  the  Asphalt  primer  over  the 
emulsion  is  that  the  asphalt  that  is  cut  with  a  solvent  can  be 
handled  with  an  air-gun  at  much  higher  pressures,  and  thus 
with  greater  penetration,  than  the  emulsion  can  be  handled. 
If  too  great  pressure  is  used  with  the  emulsion,  the  air-gun  is 
liable  to  foul  in  the  nozzle  and  clog;  because  the  excessive 
pressure  tends  to  force  too  much  water  out  of  the  emulsion 
and  coagulate  the  asphalt  in  the  nozzle. 


STRUCTURAL  SUGGESTIONS  239 

Emulsified  asphalt  plastic  is  simply  emulsified  asphalt  mixed 
by  mechanical  means  in  suitable  proportion  with  asbestos  fibre 
and  fine  sand  or  other  more  suitable  mineral  aggregates,  to 
form  a  plastic  material  resembling  Portland  cement  mortar  in 
consistency  and  suitability  for  application  with  trowel  over 
corkboard  surfaces.  The  advantage  offered  by  a  suitable 
emulsified  asphalt  plastic  as  a  protective  coating  for  corkboard 
insulation,  as  compared  with  factory  ironed-on  mastic  finish 
corkboard,  is  found  in  the  versatility  of  the  plastic  emulsion. 
Except  for  the  contingency  of  freezing  weather,  emulsified 
asphalt  plastic  may  be  applied  on  the  job  much  like  plaster, 
to  any  areas  desired,  at  any  time;  and,  furthermore,  a  suitable 
emulsified  asphalt  plastic  may  be  applied  so  as  to  present  a 
continuous  surface  that  is  sufficiently  elastic  to  withstand 
without  cracking  the  contraction  and  expansion  incident  to 
cold  storage  rooms,  while  it  may  be  difficult  to  have  the  joints 
between  factory  ironed-on  mastic  finish  corkboards  effectually 
sealed  against  the  same  forces.  However,  the  factory  ironed- 
on  mastic  joints  can  be  properly  sealed,  under  adequate  super- 
vision and  with  reasonable  care. 

The  choice  between  the  factory  finish  and  the  plastic 
emulsion  should  rest  entirely  upon  all  the  facts  surrounding 
each  case. 


CHAPTER  XIII. 

COMPLETE  SPECIFICATIONS  FOR  THE  ERECTION 
OF  CORKBOARD. 

102. — Scope  and  Purpose  of  Specifications. — These  specifi- 
cations and  illustrations  are  intended  to  show  corkboard  insu- 
lation adapted  to  practically  every  type  of  construction  to  be 
found  in  old  buildings  or  to  be  employed  in  new  structures, 
which  specifications  long  experience  has  demonstrated  to  be 
practical.  In  many  instances,  however,  more  than  one  specifi- 
cation is  given  for  the  erection  of  corkboard  to  a  given  sur- 
face, and  no  recommendation  is  made  as  to  preference ;  be- 
cause the  use  of  each  and  every  one  of  these  specifications  is 
a  matter  of  selection  based  on  experience  and  a  knowledge  of 
all  the  conditions  of  the  case,  as  previously  elaborated. 

The  thickness  of  corkboard  to  use  must  be  suited  to  the 
temperatures  to  be  maintained,  and  to  a  less  degree  to  several 
other  factors  that  will  vary  in  each  case,  all  as  noted  in 
Chapter  XII. 

These  specifications  comprise  the  following: 

103. — Walls. — Stone,  concrete  or  brick: 

(1)  Single  layer,  in  Portland  cement. 

(2)  Single  layer,  in  Asphalt  cement. 

(3)  Double    layer,   first    in    Portland    cement,    second    in 

Asphalt   cement. 

(4)  Double  layer,  both  in  Portland  cement. 

(5)  Double  layer,  both  in  Asphalt  cement 

104.— Walls.— Wood: 

(6)  Single  layer,  in  Asphalt  cement. 

(7)  Double  layer,  both  in  Asphalt  cement. 

105. — Ceilings. — Concrete : 

(8)  Single  layer,  in  Portland  cement. 

(9)  Double  layer,  both  in  Portland  cement. 

(10)   Double    layer,    first    in   Portland    cement,    second    in 
Asphalt   cement. 

240 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION        241 

(11)  Single  layer,  in  forms  before  concrete  is  poured. 

(12)  Double    layer,    first    in    forms    before    concrete    is 

poured,  second  in  Portland  cement. 

(13)  Double    layer,    first    in    forms    before    concrete    is 

poured,  second  in  Asphalt  cement. 

106. — Ceilings. — Self-supported: 

(14)  Double  layer,  T-irons  and  Portland  cement  core. 

107.— Ceilings.— Wo  o  d : 

(15)  Single  layer,  in  Asphalt  cement. 

(16)  Double  layer,  both  in  Asphalt  cement. 

108. — Roofs. — Concrete  or  wood: 

(17)  Single  layer,  in  Asphalt  cement. 

(18)  Double  layer,  both  in  Asphalt  cement. 

109.— Floors.— Wood : 

(19)  Single  layer,  in  Asphalt  cement,  concrete  finish. 

(20)  Single  layer,  in  Asphalt  cement,  wood  finish. 

(21)  Double    layer,    both    in    Asphalt    cement,    concrete 

finish. 

(22)  Double  layer,  both  in  Asphalt  cement,  wood  finish. 

110. — Floors. — Concrete: 

(23)  Single  layer,  in  Asphalt  cement,  concrete    finish. 

(24)  Single  layer,  in  Asphalt  cement,  wood  finish. 

(25)  Double    layer,    both    in    Asphalt    cement,    concrete 

finish. 

(26)  Double  layer,  both  in  Asphalt  cement,  wood  finish. 

111. — Partitions. — Stone,  concrete  or  brick: 

(See  103. — Walls. — Stone,  concrete  or  brick.) 

1 12.— Partitions.— Wood : 

(27)  Single  layer,  between  studs,  joints  sealed  in  Asphalt 

cement. 

(28)  Double  layer,  first  between  studs  with  joints  sealed 

in  Asphalt  cement,  second  in  Asphalt  cement. 

113. — Partitions. — Solid  cork: 

(29)  Single  layer,  joints  sealed  in  Asphalt  cement. 

(30)  Double  layer,  first  with  joints  sealed  in  Asphalt  ce- 

ment, second  in  Portland  cement. 

(31)  Double    layer,    first    with    joints    sealed    in    Asphalt 

cement,  second  in  Asphalt  cement. 

114.— Tanks.— Freezing: 

(32)  Double    layer   on   bottom,   both   in   Asphalt    cement, 

granulated  cork  fill  on  sides  and  ends. 
(23)  Double   layer   on   bottom,   both  in   Asphalt   cement; 
double   layer  on  sides  and  ends,  both  in  Asphalt 
cement. 

(34)  Double    layer   on   bottom,   both   in   Asphalt   cement; 

single  layer  on  sides  and  ends  against  studs,  with 
granulated  cork  fill. 

115. — Finish. — Walls  and  ceilings: 

(35)  Portland  cement  plaster,  in  two  coats. 

(36)  Factory  ironed-on  mastic  finish,  joints  sealed. 

(37)  Glazed  tile  or  brick,  in  Portland  cement. 

(38)  Emulsified  asphalt  plastic,  in  two  coats. 


242 


CORK  INSULATION 


116. — Finish. — Floors : 

(39)  Concrete. 

(40)  Wood. 

(41)  Galvanized  metal. 

117. — Miscellaneous  Specifications: 

(42)  Ends  of  beams  or  girders  extending  into  walls. 

(43)  Rat  proofing. 

(44)  Portland  cement  mortar. 

(45)  Asphalt  cement. 

(46)  Asphalt  primer. 


• 

^ 

' 

CORKBOARD 

4 

' 

■ 

- 

LLLVATION 

MORTAR 

FIG.   82.— WALLS;   STONE,  CONCRETE  OR  BRICK 


Fl  NISM 
CORKSOARD 
PORTLAMD      CtN 


ARTICLE   103   (1). 


103. — Walls. — Stone,  concrete  or  brick. 

(1)  Single  layer,  in  Portland  cement. 

To  the  reasonably  smooth  and  clean  .  .  .  walls  to  be  insu- 
lated, one  layer  of  .  ,  .-inch  pure  corkboard  shall  be  erected  in 
a  J^-inch  bedding  of  Portland  cement  mortar,  with  all  vertical 
joints  broken  and  all  joints  butted  tight.  To  the  surface  of 
the  insulation  shall  then  be  applied  a  finish  as  selected. 

103. — Walls. — Stone,  concrete  or  brick   (continued). 

(2)  Single  layer,  in  Asphalt  cement. 

To  the  reasonably  smooth  and  clean  .  .  .  walls  to  be  insu- 
lated, shall  first  be  applied  with  brush  or  air-gun  two  uniform, 
continuous  coats  of  Asphalt  primer,  to  consist  of  one  gallon 
per  75  square  feet  for  brick  surfaces  or  per  100  square  feet  for 
concrete  surfaces  for  the  first  coat,  and  one  gallon  per  125 
square  feet  for  brick  or  concrete  for  the  second  coat.  To  this 
prepared  surface,  one  layer  of  ...-inch  pure  corkboard  shall 
be   erected   in   hot   Asphalt   cement,   with   all   vertical   joints 


1 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION        243 


broken  and  all  joints  butted  tight  and  sealed  in  the  same  com- 
pound. To  the  surface  of  the  insulation  shall  then  be  applied 
a  finish  as  selected. 


1/ 1/" 

T 

CORKBOARD 

7 

' 

.  FINISH 
C  ORKBOARO 
A5PMALT     CE.ME.NT 


EILELVATION 


FIG.  83.— WALLS;  STONE,  CONCRETE  OR  BRICK.     ARTICLE  103   (2). 

103. — Walls. — Stone,  concrete  or  brick  (continued). 


..    .,,    I. 

■       i    '     1 

\ 

1 

FIRST      LA 
CORKBO/ 

YeR\ 

RD        H 

SECOND     LAYER ^ 

! 

.__j_._ 

\                         i 

FINISH 

CORKBOARD 

ASPHALT    CEMENT 

CORKBOARD 

PORTLAND      CEMENT      MORTAR 


ELEVATION 


FIG.  84.— WALLS;   STONE,  CONCRETE  OR  BRICK.     ARTICLE  103   (3). 

(3)     Double  layer,  first  in   Portland   cement,  second  in 
Asphalt  cement. 

To  the  reasonably  smooth  and  clean  .  .  .  walls  to  be  insu- 
lated, one  layer  of  .  .  .-inch  pure  corkboard  shall  be  erected  in 
a  54-inch  bedding  of  Portland  cement  mortar,  with  all  vertical 
joints  broken  and  all  joints  butted  tight.     To  the  first  course, 


244 


CORK  INSULATION 


a  second  layer  of  .  .  .-inch  pure  corkboard  shall  be  erected  in  ! 

hot  Asphalt   cement,   additionally   secured   to   the   first   with  | 

wood  skewers,  with  all  joints  in  the  second  course  broken  , 

with  respect  to  all  joints  in  the  first  course  and  all  joints  \ 

butted  tight  and  sealed  in  the  same  compound.     To  the  sur-  ; 

face  of  the  insulation  shall  then  be  applied  a  finish  as  selected.  | 

103. — Walls. — Stone,  concrete  or  brick  (continued).  | 
(4)     Double  layer,  both  in  Portland  cement.  ■ 
To  the  reasonably  smooth  and  clean  .  .  .  walls  to  be  insu- 
lated, one  layer  of  .  .  .-inch  pure  corkboard  shall  be  erected  in  j 
a  i/4-inch  bedding  of  Portland  cement  mortar,  with  all  vertical  i 


^ 

1/^            1 

— 1 

1 
SECOND 

LAYER 

\          OF 

CORI 

LBOARD 

r 

1 

' 

,       FIRST       LA~ER 
OF     CORKBC  ARD 

\ 

\ 

\ 

1 

- 

' 

)                  1 

CORKBOARD 

PORTLAND     CEMCNT     MORTAR 

CORKBOARD 

PORTLAND     CEMENT     MORTA' 


ELLLVATION 


FIG.  85.— WALLS;   STONE,  CONCRETE  OK  BRICK.     ARTICLE  103    (4). 

joints  broken  and  all  joints  butted  tight.     To  the  surface  of 
the  insulation  shall  then  be  applied  a  finish  as  selected. 

103. — Walls. — Stone,  concrete  or  brick  (continued). 

(5)     Double  layer,  both  in  Asphalt  cement. 

To  the  reasonably  smooth  and  clean  .  .  .  walls  to  be  insu- 
lated, shall  first  be  applied  with  brush  or  air-gun  two  uniform, 
continuous  coats  of  Asphalt  primer,  to  consist  of  one  gallon 
per  75  square  feet  for  brick  surfaces  or  per  100  square  feet 
for  concrete  surfaces  for  the  first  coat,  and  one  gallon  per  125 
square  feet  for  brick  or  concrete  for  the  second  coat.  To  this 
prepared  surface,  one  layer  of  ...-inch  pure  corkboard  shall 
be  erected  in  hot  Asphalt  cement,  with  all  vertical  joints 
broken  and  all  joints  butted  tight  and  sealed  in  the  same 
compound.  To  the  first  course,  a  second  layer  of  ...-inch 
pure  corkboard  shall  be  erected  in  hot  Asphalt  cement,  addi- 


k 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION        245 


tionally  secured  to  the  first  with  wood  skewers,  with  all 
joints  in  the  second  course  broken  with  respect  to  all  joints 
in  the  first  course  and  all  joints  butted  tight  and  sealed  in  the 


^ 

f     "■             II 

/ 

1 
r 

FIRST       LA 
OF     CORKB 

r^^    1  i 

/       1 

/SECOND      LAYER 

1 
1 
1_ 

1 

7 

/ 

OF     CORkIoARd" 

1 

FINISH 
CORKBOARD 
ASPHALT      CEMENT 
CORKBOARD 
ASPHALT      CE.ME.NT 


LLEVATION 


FIG. 


-WALLS;  STONE,  CONCRETE  OR  BRICK.     ARTICLE  103   (5). 


same  compound.     To  the  surface  of  the  insulation  shall  then 
be  applied  a  finish  as  selected. 
104.— Walls.— Wood. 


^ 

s. 


CR055 
SECTION 


■ 

^1 

CORKBOARD 

' 

' 

A ji 

— t/1 

FINISH 
CORKBOARD 
ASPHALT     CEMENT 
SHEATHING 


ELLELVATI  ON 


FIG.    87.— WALLS;    WOOD.      ARTICLE    104    (6). 

(6)     Single  layer,  in  Asphalt  cement. 

To  the  reasonably  smooth  and  clean  walls  to  be  insulated 
(consisting  of  ^-inch  T.  &  G.  sheathing  over  wall  studding), 


246 


CORK  INSULATION 


one  layer  of  ...-inch  pure  corkboard  shall  be  erected  in  hot 
Asphalt  cement,  additionally  secured  with  galvanized  wire 
nails,  with  all  vertical  joints  broken  and  all  joints  butted  tight 
and  sealed  in  the  same  compound.  To  the  surface  of  the  insu- 
lation shall  then  be  applied  a  finish  as  selected. 

104.— Walls. — Wood  (continued). 

(7)     Double  layer,  both  in  Asphalt  cement. 

To  the  reasonably  smooth  and  clean  walls  to  be  insulated 
(consisting  of  ^-s-inch  T.  &  G.  sheathing  over  wall  studding), 
one  layer  of   .  ..-inch  pure  corkboard  shall  be  erected  in  hot 


V" 

\ 

■^ 

-V 

1 
1 

--T 

' 

s 

^ 

\ 

V- 

— r K 

' 

FIRST 
OF    COR 

LAYLR 
KBOARO 

' 

' 

^ 

SECOND      LA 
OF      CORKB 

)ARD    1 

\ 

1 
J- 

! 

' 

-^/l- 

/*  1          [    -1 

FINII3M 
CORKBOARD 
ASPHALT    CEMEMT 
CORKBOARD 
ASPi-iAt-T     CEME.NT 
SMEATMINC; 


ELEVATION 


FIG.    88.— WALLS;   WOOD.     ARTICLE    104    (7). 


Asphalt  cement,  additionally  secured  with  galvanized  wire 
nails,  with  all  vertical  joints  broken  and  all  joints  butted  tight 
and  sealed  in  the  same  compound.  To  the  first  course,  a 
second  layer  of  . .  .-inch  pure  corkboard  shall  be  erected  in 
hot  Asphalt  cement,  additionally  secured  to  the  first  with 
wood  skewers,  with  all  joints  in  the  second  course  broken  with 
respect  to  all  joints  in  the  first  course  and  all  joints  butted 
tight  and  sealed  in  the  same  compound.  To  the  surface  of  the 
insulation  shall  then  be  applied  a  finish  as  selected. 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION         247 

105. — Ceilings. — Concrete. 

(8)     Single  layer,  in  Portland  cement. 

To  the  reasonably  smooth  and  clean  concrete  ceiling  sur- 
face to  be  insulated,  one  layer  of .  .  .-inch  pure  corkboard  shall 
be  erected  in  a  ^-inch  bedding  of  Portland  cement  mortar, 
with  all  transverse  joints  broken  and  all  joints  butted  tight, 


C  E.  I  l_l  NG 


'm%m^mmtm^^;^^><^M><^m^ 


Fl  NISM 
CORKBOARD 
PORTLAND     CLME-NT    MORTAR- 


CROSS 
SECTION 


1 

1 

CORKBOARD 

' 

7 

a 

PLAN       OF      CEILINQ 

FIG.  89.— CEILING;   CONCRETE.     ARTICLE   105    (8). 

and  the  corkboards  propped  in  position  until  the  cement  sets. 
To  the  surface  of  the  insulation  shall  then  be  applied  a  finish 
as  selected. 

105. — Ceilings. — Concrete  (continued). 

(9)     Double  layer,  both  in  Portland  cement. 

To  the  reasonably  smooth  and  clean  concrete  ceiling  sur- 
face to  be  insulated,  one  layer  of  . .  .-inch  pure  corkboard  shall 
be  erected  in  a  >^-inch  bedding  of  Portland  cement  mortar 
with  all  transverse  joints  broken  and  all  joints  butted  tight, 
and  the  corkboards  propped  in  position  until  the  cement  sets. 
To  the  first  course,  a  second  layer  of  . .  .-inch  pure  corkboard 
shall  be  erected  in  a  ><-inch  bedding  of  Portland  cement  mor- 
tar, additionally  secured  to  the  first  with  wood  skewers, 
with  all  joints  in  the  second  course  broken  with  respect  to  all 
joints  in  the  first  course  and  all  joints  butted  tight.  To  the  sur- 
face of  the  insulation  shall  then  be  applied  a  finish  as  selected. 


248 


CORK  INSULATION 


CE/LING 


:-)::):-:^)::):^::x-):m 


2^ 


■^m^^:^-^ 


PORTLAND      CE:^ 
CORKBOARD  

riMist-f  


[E.NT    MORTAR. 


CROSS 
SECTION 


ly 

V     ■     i     r    1 

I 

;                                    J 

' 

FIRST          UAYEIR. 
OP          CORKBOAvRD 

\ 

1 .       _|       . 

\7^ 

1 

\ 

1 

'  i 

\ 

s^coMD        i_ave:r 

OF           lCORK.e.OARC3 

p 

\ 

^         ,,i    .; 

1 

PLAN        or     OEllLINq 

FIG   '.:,    -c::lLI^G^;  cc^:;c.  lti..    :..  ■;  f 


ESI 


m^mm^yym-:^ 


'^i  ■  >■■----■ 


OR.OSS 

SE.CTION 


•kr         ••!     T 

^ 

J'                       <, 

FIRST 
OF           CO 

LAVE.R        ]i 

1 

"'^"■7 

• 

c 

1 

^ 

StCcjMD            L.AVe.« 

or       JcoRK.oo>^.«>        < 

' 

\ 

•1- 

. 

,     S        .1  .J 

PLAN        OF     CEIIUNQ 
FIG.   91.— CEILINGS;   CONCRETE.     ARTICLE   105    (10). 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION        249 

105. — Ceilings. — Concrete  (continued). 

(10)  Double  layer,  first  in  Portland  cement,  second  in 
Asphalt  cement. 

To  the  reasonably  smooth  and  clean  concrete  ceiling  sur- 
face to  be  insulated,  one  layer  of  .  .  .-inch  pure  corkboard  shall 
be  erected  in  a  5^-inch  bedding  of  Portland  cement  mortar, 
with  all  transverse  joints  broken  and  all  joints  butted  tight, 
and  the  corkboards  propped  in  position  until  the  cement  sets. 
To  the  first  course,  a  second  layer  of  .  .  .-inch  pure  corkboard 
shall  be  erected  in  hot  Asphalt  cement,  additionally  secured 
to  the  first  with  wood  skewers,  with  all  joints  in  the  second 
course  broken  with  respect  to  all  joints  in  the  first  course  and 
all  joints  butted  tight  and  sealed  in  the  same  compound.  To 
the  surface  of  the  insulation  shall  then  be  applied  a  finish  as 
selected. 

105. — Ceilings. — Concrete  (continued). 


WOOD  form; 
CORKBOARD 
GALV.     WIRE-     NAILS. 

FINISM      TO     BE.     APPLIED     

AFTE.R      FORM     IS     RCMOVE-D 


I 

^A kA 

CO  R  K  B  OA  R  D 

7 

" 

1                                                        1                        1 

PLAN       OF       CEILING 
FIG.   92.— CEILINGS;   CONCRETE.     ARTICLE   105    (11). 


(11)     Single  layer,  in  forms  before  concrete  is  poured. 

In  the  concrete  ceiling  forms,  constructed  by  another  con- 
tractor ...inches  deeper  than  would  otherwise  be  necessary, 
one  layer  of  .  .  .-inch  pure  corkboard  shall  be  laid  down,  with 
all  transverse  joints  broken  and  all  joints  butted  tight,  and 


250 


CORK  INSULATION 


into  which  corkboard  long  galvanized  wire  nails  shall  be  driven 
obliquely.  Into  these  forms  and  over  this  insulation  the  con- 
crete contractor  shall  pour  the  concrete.  To  the  under  surface 
of  the  insulation,  after  the  concrete  contractor  has  removed 
the  forms,  shall  then  be  applied  a  finish  as  selected. 

105. — Ceilings. — Concrete  (continued). 

(12)  Double  layer,  first  in  forms  before  concr'ite  is 
poured,  second  in  Portland  cement. 

In  the  concrete  ceiling  forms,  construed  by  another  con- 
tractor .  .  .  inches  deeper  than  would  otherwise  be  necessary, 


^ 


I,  'V^ 


WOOD  f=ORM_ 
CORK  BOARD  - 
GM_V.      WIRE.    NAILS. 


i^^m 


^,'A 


^    <  "       ^ 


CROSS    SECTION 

1_  NJOTt:       APTtR       FORM      IS     RE- 
MOVED   A    SECOND     COURSE.    OF 
CORKBOARD     SMALL     BE.     APPLIED    TO 
TME      FIRST      IN     A      £"BED     OF    PORT- 
LAMD     CEMENT     MORTAR.      rINISMTO 
BE      APPLIED    TO    TME     EyPOSED    SURFACE 


PLAN       OF     CELILING 
FIG.  93.— CEILINGS;   CONCRETE.     ARTICLE   105    (12). 

one  layer  of  .  .  .-inch  pure  corkboard  shall  be  laid  down,  with 
all  transverse  joints  broken  and  all  joints  butted  tight,  and 
into  which  corkboard  long  galvanized  wire  nails  shall  be 
driven  obliquely.  Into  these  forms  and  over  this  insulation 
the  concrete  contractor  shall  pour  the  concrete.  After  the 
forms  have  been  removed  by  the  concrete  contractor,  a  sec- 
ond layer  of  ...-inch  pure  corkboard  shall  be  erected  to  the 
underside  of  the  first  course  in  a  ^-inch  bedding  of  Port- 
land cement  mortar,  additionally  secured  with  galvanized 
wire  nails,  with  all  joints  in  the  second  course  broken  with 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION        251 


respect  to  all  joints  in  the  first  course  and  all  joints  butted 
tight.  To  the  surface  of  the  insulation  shall  then  be  applied 
a  finish  as  selected. 

105. — Ceilings. — Concrete  (continued). 

(13)  Double  layer,  first  in  forms  before  concrete  is 
poured,  second  in  Asphalt  cement. 

In  the  concrete  ceiling  forms,  constructed  by  another  con- 
tractor .  . .  inches  deeper  than  would  otherwise  be  necessary, 
one  layer  of  . .  .-inch  pure  corkboard  shall  be  laid  down,  with 


C  E  I  LIWG 


FORM  J 


C0RK60ARD 
CALV.     WIRE.    NAILS 


^^T-^^ 


■^■/^^./.-^r^l 


CROSS     SECTION 

.NOTt:    AFTER     FORM    IS    RE-MOVtO 
A      SE.COMD        COURSE.     OF      CORK- 
BOARD      SHALL      BE      APPLIED     TO 
THt       PIRST      IM     A     BtO     OF    HOT 
ASPHALT         CE.ME.K4T.         FINISH 
5HAI_L.        BE.       APPLIED      TO    THE 

EVPOSE.D      Surface,. 


\A 

"( 

<^ \ •" 1 

5E.C 

"oV" 

3ND     1     L.AVE.R 
CORKBOARP   ~ 

FIRST        L 
OF      CORK 

AVER  ^v 
BOARD 

, 

7 

V          ; 

-. 

1         1 

PLAN      OF     CELILING 
FIG.  94.— CEILINGS;   CONCRETE.     ARTICLE   105    (13). 

all  transverse  joints  broken  and  all  joints  butted  tight,  and 
into  which  corkboard  long  galvanized  wire  nails  shall  be 
driven  obliquely.  Into  these  forms  and  over  this  insulation 
the  concrete  contractor  shall  pour  the  concrete.  After  the 
forms  have  been  removed  by  the  concrete  contractor,  a  sec- 
ond layer  of  ...-inch  pure  corkboard  shall  be  erected  to  the 
underside  of  the  first  course  in  hot  Asphalt  cement,  addition- 
ally secured  with  galvanized  wire  nails,  with  all  joints  in  the 
second  course  broken  with  respect  to  all  joints  in  the  first 
course  and  all  joints  butted  tight  and  sealed  in  the  same  com- 
pound. To  the  surface  of  fhe  insulation  shall  then  be  applied 
a  finish  as  selected. 


252 


CORK  INSULATION 


106. — Ceilings — Self-supported. 

(14)     Double  layer,  T-irons  and  Portland  cement  core. 
Upon  the  top  edges   of  the   side  wall   insulation  shall  be 
placed,    running   the    short   way   of   the   room,*    2x2xy^-\nch, 


CROSS    SECTION 

("PORTLAND     CEMENT    PLASTER 

CORKBOARD 

2"-Z«^"  TE.£      IRON 

^"PORTLAND    CEMENT      BACKING 

CORKBOARD 

FINISH 


FIG.  95.— CEILINGS;   SELF-SUPPORTING.     ARTICLE   106   (14). 


or  2x2x5/16-inch  T-irons,  spaced  at  a  distance  of  12  inches 
between  the  vertical  sections  of  the  T-irons  (not  from  center 
to  center).  Upon  the  flanges,  or  horizontal  sections,  of  the  T- 
irons,  one  layer  of  .  .  .-inch  pure  corkboard  shall  be  carefully 
put  in  place,  with  all  joints  butted  tight.  To  the  top  surface 
of  the  insulation  shall  then  be  applied  a  1-inch  thick  Portland 
cement  finish,  mixed  in  the  proportion  of  one  part  Portland 
cement  to  two  parts  clean,  sharp  sand. 

To  the  under  side  of  the  first  course,  a  second  layer  of 
. .  .-inch  pure  corkboard  shall  be  erected  in  a  ^-inch  bedding 
of  Portland  cement  mortar,  additionally  secured  to  the  first 
with  galvanized  wire  nails,  all  joints  in  the  second  course 
broken  with  respect  to  all  joints  in  the  first  course  and  all 
joints  butted  tight.  To  the  surface  of  the  insulation  under- 
neath shall  then  be  applied  a  finish  as  selected. 

1 07 . — Ceilings. — Wood. 

(15)     Single  layer,  in  Asphalt  cement. 

To  the  reasonably  smooth  and  clean  ceiling  surface  to  be 
insulated  (consisting  of  J^-inch  T.  &  G.  sheathing  to  joists), 
one  layer  of  . .  .-inch  pure  corkboard  shall  be  erected  in  hot 


*About  10  feet  is  the  maximum  width  that  may  be  spanned  safely  by  T-irons  car- 
rying double  layer  of  corkboard,  and  following  this  specification.  It  is  not  perrnis- 
sable  to  double  the  span  and  center-support  the  T-irons  by  rods  fastened  to  ceiling 
of  buildino;  above  ;  because  water  will  be  condensed  on  the  cool  surfaces  of  these  rods 
and  will  follow  through  into  ceilini?  insulation  below,  tending  to  destroy  it  or  other- 
wise make  it  unfit  for  service  within  a  year. 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION 


253 


Asphalt    cement,    additionally    secured    with   galvanized   wire 
nails,  with  all  transverse  joints  broken  and  all  joints  butted 


SHEATMING      J  f 


ASPHALT      CEMENT   _J 

CORKBOARD    

FINISH         


VV-A 


CROS5     SECTION 


, 

'        1 

\ 

7 

CORK  BOARD 

^' 

^ 

'■ 

1                          ,                                            ^                                               1 

PLAN      OF    CLILING 

FIG.   96.— CEILINGS;    WOOD.      ARTICLE    107    (15). 

tight  and  sealed  in  the  same  compound.     To  the  surface  of 
the  insulation  shall  then  be  applied  a  finish  as  selected. 
107. — Ceilings.— Wood  (continued). 

(16)  Double  layer,  both  in  Asphalt  cement. 

To  the  reasonably  snfooth  and  clean  ceiling  surface  to  be 
insulated  (consisting  of  %-inch  T.  &  G.  sheathing  to  joists), 
one  layer  of  .  .  .-inch  pure  corkboard  shall  be  erected  in  hot 
Asphalt  cement,  additionally  secured  with  galvanized  wire 
nails,  with  all  transverse  joints  broken  and  all  joints  butted 
tight  and  sealed  in  the  same  compound.  To  the  first  course, 
a  second  layer  of  . .  .-inch  pure  corkboard  shall  be  erected  in 
hot  Asphalt  cement,  additionally  secured  to  the  first  with 
wood  skewers,  with  all  joints  in  the  second  course  broken 
with  respect  to  all  joints  in  the  first  course  and  all  joints 
butted  tight  and  sealed  in  the  same  compound.  To  the  sur- 
face of  the  insulation  shall  then  be  applied  a  finish  as  selected. 

108. — Roofs. — Concrete  or  wood. 

(17)  Single  layer,  in  Asphalt  cement. 

To  the  reasonably  smooth  and  clean    .  .  .    roof  area  to  be 


254 


CORK  INSULATION 


insulated,  one  layer  of  . .  .-inch  pure  corkboard  shall  be  laid 
down  in  hot  Asphalt  cement,  with  all  transverse  joints  broken 


5HE.AT 

ASPHALT  CELN 
CORKBOARD 
ASPHALT       CEIMENIT 

CORK  BOARD  

FIMISH    


^     1     ; 

V 

1 

\f 

^ 

, 

s 

SECOND        LAVE.R 

> 

FIR5T 
OF       COP 

LAVE. 
5KBOA 

A 

OF 

COfiKBOARD 

RD 

^         -J- 

- 

7 

/ 

1 

PLAN       OF  CEIILING 
FIG.   97.— CEILINGS;    WOOD.      ARTICLE    107    (16). 

and  all  joints  butted  tight  and  sealed  in  the  same  compound.* 
The  roofing  contractor  shall  then  apply,  to  the  surface  of  the 
insulation,  a  roofing  as  required. 

108. — Roofs.— Concrete  or  wood  (continued). 

(18)     Double  layer,  both  in  Asphalt  cement. 

To  the  reasonably  smooth  and  clean  .  .  .  roof  area  to  be 
insulated,  one  layer  of  ...-inch  pure  corkboard  shall  be  laid 
down  in  hot  Asphalt  cement,  with  all  transverse  joints  broken 
and  all  joints  butted  tight  and  sealed  in  the  same  compound. 
To  the  first  course,  a  second  layer  of  .  .  .-inch  pure  corkboard 
shall  then  be  laid  down  in  hot  Asphalt  cement,  with  all  joints 
in  the  second  course  broken  with  respect  to  all  joints  in  the 
first  course  and  all  joints  butted  tight  and  sealed  in  the  same 

NOTE — The  wall  insulation  should  be  carried  up  so  as  to  connect  with  the  'oof 
insulation,  whecever  possible ;  and  in  such  cases,  insert  the  following  sentence  at  the 
point  starred  (*)  in  the  above  specification:  "The  roof  insulation  shall  connect  with 
the  wall  insulation,  the  joint  being  sealed  with  hot  Asphalt  cement." 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION        255 


ROOFINa     BY    Atv40THE.R     CONTRACTOR. 


fm^Mmmmm 


SECTION     A-A 


CORKBOARD . 
ASPHALT  CEMCNT_| 
CONCRETE  ROOF    5LAB_1 


\j^ 


SECTION  SHOWING  HOW 
WALL  AND  ROOF  mSUL- 
ATION    MAY    BE.    CONNECTED         ^ 


r 

" 

CORKBOARD 

•= 

r 

' 

< 

, 

PLAN     OF     ROOF 
FIG.    98.— ROOFS;    CONCRETE   OR    WOOD.      ARTICLE    108    (17). 


ROOFIK/G     BY      ANOTHtR     CONTRACTOR 


SECTION      SHOWINq 
MOW    WALL    AND    ROOF 
INSULATIOM       MAY      BE. 
CONNECTED. 


CR05S     SECTION 

CORKBOARD — 
ASPHALT      CE:ME.NT_ 
5HE.ATMING_ 


^ 

CORKBOARD 

. 

yi ^ 

.          ] 

PLAN      OF     ROOF 
FIG.  99.— ROOFS;  CONCRETE  OR  WOOD.     ARTICLE  108   (18). 


256 


CORK  INSULATION 


compounds.*      The    roofing    contractor    shall    then    apply,    to 
the  surface  of  the  insulation,  a  roofing  as  required. 

109.— Floors.— Wood. 

(19)     Single  layer,  in  Asphalt  cement,  concrete  finish. 
To  the  reasonably  smooth  and  clean  wood  floor  to  be  in- 
sulated  (consisting  of  1^-inch  T.  &  G.  flooring  over  joints), 


iy a 

1 

r 

CORK.BOARD 

^ 

' 

. 

PORTLAND    CEMENT    FINISH. 

CONCRELTE 

ASPHALT      CE.ME.NT_ 
CORKBOARD 
ASPHALT      CE.ME.NT_, 
FLOORINJG 


PLAN 

OF    FLOOR 


CROSS       SECTION 
FIG.    100.— FLOORS;  WOOD.     ARTICLE   109    (19j. 

one  layer  of  .  .  .-inch  pure  corkboard  shall  be  laid  down  in  hot 
Asphalt  cement,  with  all  transverse  joints  broken  and  all  joints 
butted  tight,  and  the  top  surface  then  flooded  with  hot  Asphalt 
cement.  Over  the  surface  of  the  insulation  shall  then  be 
applied  a  concrete  floor  finish  as  selected. 

109. — Floors. — Wood  (continued). 
(20)     Single  layer,  in  Asphalt  cement,  wood  finish. 
To  the  reasonably  smooth  and  clean  wood  floor  to  be  in- 
sulated (consisting  of  1^-inch  T.  &  G.  flooring  over  joists), 

NOTE — The  wall  insulation  should  be  carried  up  so  as  to  connect  with  the  roof 
insulation,  wherever  possible;  and  in  such  cases,  insert  the  following  sentence  at  the 
point  starred  (*)  in  the  above  specification:  "The  roof  insulation  shall  connect  with 
the  wall  insulation,  the  joint  being  sealed  with  hot  Asphalt  cement." 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION        257 

2-inch  X  ...-inch  sleepers  shall  be  put  in  place  on  edge  on 
38-inch  centers.  Between  these  sleepers,  one  layer  of  .  .  .-inch 
pure  corkboard  shall  be  laid  down  in  hot  Asphalt  cement, 
with  all  joints  butted  tight,  and  the  top  surface  then  flooded 


, 

A 

■ 

^ 

'•^-^ SLEltPtRS 

7 

CORKBOARD 

^ 

f=l_OORING 
ASPHALT     CEME.NT. 
CORKBOARD 


PLAN 

OF    FLOOR 


CR05S      SECTION 
FIG.    101.— FLOORS;    WOOD.      ARTICLE    109    (20). 


with  the  same  compound.  Over  the  surface  of  the  insulation 
shall  then  be  applied  a  T.  &  G.  flooring  as  selected,  securely 
fastened  to  the  sleepers. 

109. — Floors. — Wood  (continued). 

(21)  Double  layer,  both  in  Asphalt  cement,  concrete 
finish. 

To  the  reasonably  smooth  and  clean  wood  floor  to  be  in- 
sulated (consisting  of  1^-inch  T.  &  G.  flooring  over  joists), 
one  layer  of  . .  .-inch  pure  corkboard  shall  be  laid  down  in  hot 
Asphalt  cement,  with  all  transverse  joints  broken  and  all 
joints  butted  tight.  To  the  first  course,  a  second  layer  of 
. .  .-inch  pure  corkboard  shall  be  laid  down  in  hot  Asphalt  ce- 
ment, with  all  joints  in  the  second  course  broken  with  respect 


258 


CORK  INSULATION 


to  all   joints  in   the  first   course  and   all  joints   butted  tight, 
and  the  top  surface  then  flooded  with  the  same  compound 


V                           ^i- 

— I — i^ — 

^ 

"^       1 

y 

— ~ — 

------ 

' 

FIR5T       LAVtR        [^ 
QF       CORKBOARD 

"\      JSECONJD      LAVE.R_ 
\iOF     CORKBOARD    - 

~1 

\ 

;    { 

PLAN      OF      FLOOR. 


PORTLANP     CEMLNT    FINISH 
CONCRETE- 
CORK  BOARD 


CROSS       5E.CTION 
FIG.    102.— FLQOKS;    WOOD.      ARTICLE    109    (21). 

Over  the  surface  of  the  insulation  shall   then  be  applied  a 
concrete  floor  finish  as  selected. 

109. — Floors. — Wood  (continued). 

(22)     Double  layer,  both  in  Asphalt  cement,  wood  finish. 

To  the  reasonably  smooth  and  clean  wood  floor  to  be  in- 
sulated (consisting  of  1^-inch  T.  &  G.  flooring  over  joists), 
one  layer  of  . .  .-inch  pure  corkboard  shall  be  laid  down  in  hot 
Asphalt  cement,  with  all  vertical  joints  broken  and  all  joints 
butted  tight.  Over  this  insulation,  2-inch  x  ..  .-inch  sleepers 
shall  then  be  put  in  place  on  38-inch  centers.  Between  these 
sleepers,  the  second  layer  of  . .  .-inch  pure  corkboard  shall  be 
laid  down  in  hot  Asphalt  cement,  with  all  joints  in  the  second 
course  broken  with  respect  to  all  joints  in  the  first  course 
and  all  joints  butted  tight,  and  the  top  surface  then  flooded 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION 


259 


with  the  same  compound.  Over  the  surface  of  the  insulation 
shall  then  be  applied  a  T.  &  G.  flooring  as  selected,  securely 
fastened  to  the  sleepers. 


t    '         \' 

\    SLELEPELR 

\ 

1 

N 

o 

1 

.__!__.. 

FIRST         LA 
OF       CORKE 

V.K           I          i 

1  OF       C 

D      LAYER. 

, 

v_ 

Y 

1 

PLAN       OF      FLOOR. 


ix.r.      SLEEPE.RS 
FLOORlM< 
CORKBOARP 


CROSS       SECTION 
FIG.    103.— FLOORS;    WOOD.      ARTICLE    109    (22). 

110. — Floors.— Concrete. 

(23)  Single  layer,  in  Asphalt  cement,  concrete  finish. 
To  the  reasonably  smooth  and  clean  concrete  floor  to  be 

insulated,  one  layer  pf  ...-inch  pure  corkboard  shall  be  laid 
down  in  hot  Asphalt  cement,  with  alh transverse  joints  broken 
«and  all  joints  butted  tight,  and  the  top  surface  then  flooded 
with  the  same  compound.  Over  the  surface  of  the  insulation 
shall  then  be  applied  a  concrete  floor  finish  as  selected. 

110. — Floors. — Concrete    (continued). 

(24)  Single  layer,  in  Asphalt  cement,  wood  finish. 

To  the  reasonably  smooth  and  clean  concrete  floor  to  be 
insulated,  2-inch  x  ...-inch  sleepers  shall  be  put  in  place  on 
edge  on  38-inch  centers.    Between  these  sleepers,  one  layer  of 


260 


CORK  INSULATION 


» 

1/1 

« 

CORK.BOARt> 

^ 

\\        .       \       .        n 

PLAN      OF     FLOOR. 


PORTLAND      CEME.rsJT     FINI 

51- 

- 

^■^.■■■-    ;.■■  *  ''  ^  .  •■  ■'■ 

-\:,t:'.-,:^:--::%i\ 

^'X'/^y^/^^Mm.  ^y^'/'>^:^y>>^^'>('mm: 

?t°   ■    J   .  "^    ■'   '•  '•  "^    FLOOR          SLAB        ■'^      '■^-    "^  I,  '  '."   ,  ' 

CROSS         SECTION 
FIG.    104.— FLOORS;   CONCRETE.     ARTICLE   110    (23). 


V 

UV t/l 

^ 

1 

? 

^— --^SLEE-PLRS.     . 

7 

COR  KBOARD 

•! 

1 

PLAN      OF     FLOOR 


f=LOORINC  _ 
CO'RK  BOARD 
ASPHALT     CEME.NT. 
2"''4"  SLEEPER. 


CROSS       SECTION 
FIG.    105.— FLOORS;    CONXRETE.      ARTICLE    110    (24). 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION        261 

...-inch  pure  corkboard  shall  be  laid  down  in  hot  Asphalt 
cement,  with  all  transverse  joints  broken  and  all  joints  butted 
tight,  and  the  top  surface  then  flooded  with  the  same  com- 
pound. Over  the  surface  of  the  insulation  shall  then  be 
applied  a  T.  &  G.  flooring  as  selected,  securely  fastened  to 
the  sleepers. 

110. — Floors. — Concrete    (continued). 


\^' 

b'                           '■            1 

V 

ri 

\_.         ._ 

i 

■ 

Fl  R5T        LAVELR.   ^ 
OF       CORKBOARD 

4 

l5E.CO^40         l_AVE.R 
V.        OF  corh;board 

' 

^\ 

^"""■""""Ti 

/,.    1    i ., 

PLAN      OF      FLOOR 


PORTLAND      CtMElNJT     FINI5h 

^ 

ASPMAUT     CLMENT 

-. 

■' .^-  -^-    .-^  ■  .  -  :-.  -'-  1. 

id 

:. 

^ 

.-; 

:  ■- 

V^\-^^  ::^.J\ 

.    '^'v'.'.'  ^t,.:'-/,-: ,.    ■ 

. 

....  x■^^^^■tvK-\.^:  VI 

v-V.-V.  /.■■/.■/.-/.'////)('.'/,■//, 

' ->  'A/.'///, 

'/,y.'yyAy///\ 

■j."-    •  ..*,•;'.'     Fl_OOPl          SLAB       «. 

vm 

CR05S      SECTION 

FIG.    106.— FLOORS;    CONCRETE.      ARTICLE    110    (25). 


(25)  Double  layer,  both  in  Asphalt  cement,  concrete 
finish. 

To  the  reasonably  smooth  and  clean  concrete  floor  to  be 
insulated,  one  layer  of  ...-inch  pure  corkboard  shall  be  laid 
down  in  hot  Asphalt  cement,  with  all  transverse  joints  broken 
and  all  joints  butted  tight.  To  the  first  course,  a  second 
layer  of  ...-inch  pure  corkboard  shall  be  laid  down  in  hot 
Asphalt  cement,  with  all  joints  in  the  second  course  broken 
with  respect  to  all  joints  in  the  first  course  and  all  joints 
butted  tight,  and  the  top  surface  then  flooded  with  the  same 
compound.  Over  the  surface  of  the  insulation  shall  then 
be  applied  a  concrete  floor  finish  as  selected. 


262 


CORK  INSULATION 


110. — Floors. — Concrete    (continued). 

(26)     Double  layer,  both  in  Asphalt  cement,  wood  finish. 

To  the  reasonably  smooth  and  clean  concrete  base  floor  to 
be  insulated,  one  layer  of  .  .  .-inch  pure  corkboard  shall  be  laid 
down  in  hot  Asphalt  cement,  with  all  vertical  joints  broken 


PLAN       OF      FLOOR 


Z>2.   5l_EE.PC.R5 
CORKBOARD 


CROSS      SECTION 
FIG.   107.— FLOORS;   CONCRETE.     ARTICLE   110    (26). 

and  all  joints  butted  tight.  Over  this  insulation,  2-inch  x  . . . 
-inch  sleepers  shall  then  be  put  in  place  on  38-inch  centers. 
Between  these  sleepers,  the  second  layer  of  .  .  .-inch  pure  cork- 
board  shall  be  laid  down  in  hot  Asphalt  cement,  with  all  joints 
in  the  second  course  broken  with  respect  to  all  joints  in  the 
first  course  and  all  joints  butted  tight,  and  the  top  surface 
then  flooded  with  the  same  compound.  Over  the  insulation 
shall  then  be  applied  a  T.  &  G.  flooring  as  selected,  securely 
fastened  to  the  sleepers. 

111. — Partitions. — Stone,    concrete   or  brick. 

(See  103. — Walls:  Stone,  concrete  or  brick;  specifications 
(1),  (2),  (3),  (4)  and  (5). 

Note  :  It  is  not  always  necessary  to  divide  the  total  thick- 
ness of  insulation  and  put  half  of  it  on  either  side  of  partition 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION         263 

walls ;  instead,  it  is  sometimes  sufficient  to  apply  the  total 
thickness  of  insulation  to  one  side  or  the  other,  finish  it  off 
as  desired,  and  then  apply  the  same  finish  to  the  uninsulated 
side  of  the  wall. 


V 

f \f^ 

7 

. 

CORKBOARD 

' 

'7 

> 

^. 

.^                ^ 

E.  LE.VATION 

FINISH 

CORKBOARD 

ASPHALT      eCMENT    OR 

PORTLAND    CE.ME.NT    MORTAR 

-PARTITIONS;    STONE,    CONCRETE    OR    BRICK.      ARTICLE    111. 


1 1 2  .—Partitions.— Wood. 

(27)  Single  layer,  between  studs,  joints  sealed  in  Asphalt 
cement. 

Two-inch  x  4-inch  studding  shall  be  erected  36  inches 
apart,  the  studs  secured  so  that  the  2-inch  dimension  runs 
with  the  wall  thickness.  Between  studs,  one  layer  2-inch 
corkboard  shall  be  erected  edge  on  edge,  with  all  joints  butted 
and  sealed  with  hot  Asphalt  cement,  and  each  corkboard 
secured  to  the  studs  and  additionally  to  the  adjacent  cork- 
board with  galvanized  wire  nails.  Over  the  exposed  area  of 
the  studding  shall  be  put  in  place  12-inch  wide  strips  of 
galvanized  wire  square-mesh  screen.  No.  18  gauge,  3  mesh 
(1/3-inch),  securely  stapled  to  the  studs  and  nailed  to  the 
insulation  on  both  sides  of  studs.  Where  cold  storage  doors 
are  to  be  set,  4-inch  x  . .  .-inch  permanent  studs,  with  a  lintel 
between  them,  shall  be  securely  anchored  to  the  floor  and 
ceiling  in  the  line  of  the  partition  so  as  to  form  an  opening 


264 


CORK  INSULATION 


the  size  of  the  cold  storage  door  frame;  and  after  the  parti- 
tion has  been  constructed,  the  permanent  studs  and  lintel 
shall  be  covered  on  both  sides  with  ...-inch  pure  corkboard 
secured   with   gahanized   wire   nails.     To  the   surface   of  the 


CORKBOARD 


i/— 

(i 

7 

\ 

' 

I 
I 

\ 

^ 

- 

•T' 

A^PHALT     CEMENT    ON    ALL 

OINT5 

CORKBOARD 

'' 

' 

2.. 4       STUDS 
3fa'        APAKT 

^> 

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^                      ^              r>- 

ELEVATION 

FINISH 

SQUARE    MESM     3CREE.N    OVER     STUDS 

2>'4.     STUDS     34."    APART      WITH 

CORKBOARD      BE.TWEEN 

FrNISM 

FIG.     109.— PARTITIONS;    WOOD.      ARTICLE    112     (27). 

insulation  and   over   the   wire   mesh   shall   then   be  applied  a 
finish  as  selected. 

1 12. — Partitions. — Wood  (continued) . 

(28)  Double  layer,  first  between  studs  with  joints  sealed 
in  Asphalt  cement,  second  in  Asphalt  cement. 

Two-inch  x  4-inch  studding  shall  be  erected  36  inches 
apart,  the  studs  secured  so  that  the  2-inch  dimension  runs 
with  the  wall  thickness.  Between  the  studs,  one  layer  2-inch 
pure  corkboard  shall  be  erected  edge  on  edge,  with  all  joints 
butted  and  sealed  with  hot  Asphalt  cement,  and  each  cork- 
board  secured  to  the  studs  and  additionally  to  the  adjacent 
corkboard  with  galvanized  wire  nails.  To  the  first  course,  a 
second  layer  of  .  .  .-inch  pure  corkboard  shall  be  erected  in 
hot  Asphalt  cement,  additionally  secured  with  wood  skew- 
ers, with  all  joints  in  the  second  course  broken  with  respect 
to  all  joints  in  the  first  course  and  all  joints  butted  tight  and 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION        265 

sealed  in  the  same  compound.  Over  the  exposed  area  of  the 
studding  shall  be  put  in  place  12-inch  wide  strips  of  galvanized 
wire  square-mesh  screen,  No.  18  gauge,  3  mesh  (1/3-inch), 
securely  stapled  to  the  studs  and  nailed  to  the  insulation  on 
both  sides  of  studs.     Where  cold  storage  doors  are  to  be  set. 


i 

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1 

1 

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Y 

V            5ECOkjd| 

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. 

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FIRST       LAV 
OF      CORKBO 

E.R       \               1 

AHD          1                 1 

1 

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,                    2.-4      STUDS               ^ 

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.1 

ELLELVATION 


FINISH 

CORKBOARD 

ASPHALT      CEMtNT 

2-«4       STUDS       3t."   APART    WITH 

CORKBOARD       BE-TVv'E.ELN 

SQUARE.     MESH     SCRELELKJ     OVER     STUDS 


FIG.     110.— PARTITIONS;    WOOD.      ARTICLE    112    (28). 

4-inch  X  ...-inch  permanent  studs,  with  a  lintel  between  them, 
shall  be  securely  anchored  to  the  floor  and  ceiling  in  the  line 
of  the  partition  so  as  to  form  an  opening  the  size  of  the  cold 
storage  door  frame ;  and  after  the  partition  has  been  con- 
structed, the  permanent  studs  and  lintel  shall  be  covered  on 
both  sides  with  . .  .-inch  pure  corkboard  secured  with  gal- 
vanized wire  nails.  To  the  surface  of  the  insulation  and  over 
the  wire  mesh  shall  then  be  applied  a  finish  as  selected. 

113. — Partitions. — Solid  cork. 

(29)      Single  layer,  joints  sealed  in  Asphalt  cement. 

To  form  the  partition  wall,  there  shall  be  built  up  edge 
on  edge  one  layer  of  .  .  .-inch  pure  corkboard,  with  all  vertical 
joints  broken   and   all  joints   butted   tight   and   sealed   in   hot 


266 


CORK  INSULATION 


Asphalt  cement.  Each  corkboard  shall  be  additionally  se- 
cured to  the  abutting  corkboards  and,  where  possible,  to  the 
wall,  floor  and  ceiling  insulation,  with  long  wood  skewers. 
Where  cold  storage  doors  are  to  be  set,  4-inch  x  . .  .-inch  per- 
manent studs,  with  a  lintel  between  them,  shall  be  securely 
anchored  to  the  floor  and  ceiling  in  the  line  of  the  partition 
so  as  to  form  an  opening  the  size  of  the  cold  storage  door 
frame ;  and  after  the  partition  is  constructed,  the  permanent 


W/, 

1'" J/. 

1 

' 

■» 

\ 

/ 

^^ 

SKEWERS 

\^ 

■■<'y. 

^^ 

(                         ^ 

^ 

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OORKBO/^RD 

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F-frMI.«.M 

CROSS    SECTION  E.L.E.VATION 

FIG.    111.— PARTITIONS;    SOLID    CORK.      ARTICLE    113    (29). 


studs  and  lintel  shall  be  covered  on  both  sides  with  .  ..-inch 
pure  corkboard  secured  with  galvanized  wire  nails.  To  the 
surface  of  the  insulation  shall  then  be  applied  a  finish  as 
selected. 

113. — Partitions. — Solid  cork  (continued). 

(30)  Double  layer,  first  with  joints  sealed  in  Asphalt 
cement,  second  in  Portland  cement. 

To  form  the  partition  wall,  there  shall  be  built  up  edge  on 
edge  one  layer  of  . .  .-inch  pure  corkboard,  with  all  vertical 
joints  broken  and  all  joints  butted  tight  and  sealed  in  hot 
Asphalt  cement.  Each  corkboard  shall  be  additionally  se- 
cured to  the  abutting  corkboards  and,  where  possible,  to  the 
wall,  floor  and  ceiling  insulation,  with  long  wood  skewers. 
To  the  first  course,  a  second  layer  of  . .  .-inch  pure  corkboard 
shall  then  be  erected  in  a  ^-inch  bedding  of  Portland  cement 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION        267 

mortar,  additionally  secured  to  the  first  with  wood  skewers, 
with  all  joints  in  the  second  course  broken  with  respect  to 
all  joints  in  the  first  course  and  all  joints  butted  tight.  Where 
cold  storage  doors  are  to  be  set,  4-inch  x  . .  .-inch  permanent 
studs,  with  a  lintel  between  them,  shall  be  securely  anchored 
to  the  floor  and  ceiling  in  the  line  of  the  partition  so  as  to 
form  an  opening  the  size  of  the  cold  storage  door  frame;  and 
after  the   partition   is  constructed,   the   permanent   studs  and 


m 


m 


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OF     CORKBOARD 

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FIN13M 

CORKBOARD 

PORTLAND     CE.ME.NT     MORTAR 

OORKBOARD 

FINISH 


CR055    SELCTION 


ELLE-VATION 


FIG.    112.— PARTITIONS;    SOLID   CORK.     ARTICLE    113    (30). 

lintel  shall  be  covered  ,on  both  sides  with  ...-inch  pure  cork- 
board  secured  with  galvanized  wire  nails.  To  the  surface 
of  the  insulation  shall  then  be  applied  a  finish  as  selected. 

113. — Partitions. — Solid  cork  (continued). 

(31)  Double  layer,  first  with  joints  sealed  in  Asphalt 
cement,  second  in  Asphalt  cement. 

To  form  the  partition  wall,  there  shall  be  built  up  edge  on 
edge  one  layer  of  ...-inch  pure  corkboard,  with  all  vertical 
joints  broken  and  all  joints  butted  tight  and  sealed  in  hot 
Asphalt  cement.  Each  corkboard  shall  be  additionally  secured 
to  the  abutting  corkboards  and,  where  possible,  to  the  wall, 
floor  and  ceiling  insulation,  with  long  wood  skewers.  To 
the  first   course,   a   second   layer  of    . .  ,-inch   pure   corkboard 


268 


CORK  INSULATION 


shall  then  be  erected  in  hot  Asphalt  cement,  additionally  se- 
cured to  the  first  course  with  wood  skewers,  with  all  joints 
in  the  second  course  broken  with  respect  to  all  joints  in  the 
first  course  and  all  joints  butted  tight  and  sealed  in  the  same 
compound.  Where  cold  storage  doors  are  to  be  set,  4-inch  x 
. .  .-inch  permanent  studs,  with  a  lintel  between  them,  shall  be 
securely  anchored  to  the  floor  and  ceiling  in  the  line  of  the 
partition  so  as  to  form  an  opening  the  size  of  the  cold  storage 


i 


4^ 


t 


FINISH 
CORKBOARD 
ASPHALT     CELMEJMT 
CORKBOARD 
FINISH 


CR055    5LCTION 


EILEIVATION 


FIG.    113.— PARTITIONS;   SOLID   CORK.      ARTICLE   113    (31). 

door  frame ;  and  after  the  partition  is  constructed,  the  per- 
manent studs  and  lintel  shall  be  co\ered  on  both  sides  with 
,..-inch  pure  corkboard  secured  with  galvanized  wire  nails. 
To  the  surface  of  the  insulation  shall  then  be  applied  a 
finish  as  selected. 

1 14. — Tanks. — Freezing. 

(32)  Double  layer  on  bottom,  both  in  Asphalt  cement, 
granulated  cork  fill  on  sides  and  ends. 

To  the  reasonably  smooth  and  clean  concrete  base,  of 
dimensions  2  feet  wider  and  2  feet  longer  than  the  size  of 
the  freezing  tank,  one  layer  of  .  .  .-inch  pure  corkboard  shall 
be  laid  down  in  hot  Asphalt  cement,  with  all  transverse  joints 
broken  and  all  joints  butted  tight.  To  the  first  course,  a 
second  layer  of   . .  .-inch  pure  corkboard  shall  be  laid  down 


Jk 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION       269 


in  hot  Asphalt  cement,  with  all  joints  in  the  second  course 
broken  with  respect  to  all  joints  in  the  first  course  and  all 
joints  butted  tight,  and  the  top  surface  then  flooded  with  the 
same  compound  and  left  ready  for  the  tank  to  be  set  down 
directly  on  top. 

After  the  tank  has  been  properly  set  by  others,  retaining 
walls  of  lumber  shall  be  constructed  so  as  to  leave  a  space 
1   foot  all   around  the   four*  sides  of  the  tank,   by   erecting 


£ 


i    T   e,C.  BOARDS 
2.UAVELRS    OF     PAPER 
g'  T.S.   G    BOARDi 


^ 


1^ 


-RaGRANUt-ATEO      CORK. 


CR055      SECTION    OF  TANK 
FIG.    114.— TANKS;    FREEZING.      ARTICLE    114    (32). 

2-inch  X  12-inch  studding  on  suitable  centers  at  right 
angles  against  the  sides  of  the  tank  and  then  sheathing  the 
studs  with  double  layer  J^-inch  T.  &  G.  boards  having  two 
layers  of  waterproof  paper  between.  The  studs  shall  be  care- 
fully anchored  by  dropping  them  into  depressions  in  the  con- 
crete base  and  then  wedging  them  under  and  securing  them 
with  metal  clips  to  the  flange  at  top  of  tank.  The  space  be- 
tween the  retaining  walls  and  the  tank  shall  be  filled  with 
regranulated  cork  well  temped  in  place,  and  a  curbing 
consisting  of  double  layer  %-inch  T.  &  G.  boards  with  two 
layers  of  waterproof  paper  between  shall  then  be  installed 
so  as  to  rest  on  the  flange  of  the  tank  and  cover  the  space 
filled  with  regranulated  cork. 

114. — TanKs. — Freezing   (continued). 

(33)     Double  layer  on  bottom,  both  in  Asphalt  cement; 
double  layer  on  sides  and  ends,  both  in  Asphalt  cement. 


*If  the  tank  is  to  be  set  in  a  corner  so  that  masonry  walls  of  the  building  act  as 
two  retaining  walls,  they  should  be  damp-proofed  in  a  suitable  and  thorough  manner. 


270 


CORK  INSULATION 


To  the  reasonably  smooth  and  clean  concrete  base,  o^ 
dimensions  enough  wider  and  longer  than  the  size  of  the  freez- 
ing tank  sufficient  to  overlap  the  thickness  of  insulation  on 
ends  and  sides,  one  layer  of  ..  .-inch  pure  corkboard  shall  be 
laid  down  in  hot  Asphalt  cement,  with  all  transverse  joints 
broken  and  all  joints  butted  tight.  To  the  first  course,  a  sec- 
ond layer  of  .  .  .-inch  pure  corkboard  shall  be  laid  down  in 
hot  Asphalt  cement,  with  all  joints  in  the  second  course  broken 


~~m^y 


SELCTIONAL.     PLAN 


U---4— ^=".± 

-J 

^_E.J;  O  M  p  _  _Lj*,2; 
OP     CORKBOAI 

tR." 

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^ 

^     1 

i       1      ..                           ill 

/" 

=^ 

-   STUDS  fc 

FIRST        l-AVE-B, 
OP-      CORKBOARD 

1  i                       i   i     } 

;-/ 

c  o 

l^:H!S- 

"  ■".  ■ 

..";. 

EILEVATION  CR055      5E.CTION 

FIG.    lis.— TANKS;    FREEZING.      ARTICLE    114    {2Z) . 

with  respect  to  all  joints  in  the  first  course  and  all  joints 
butted  tight,  and  the  top  surface  then  flooded  with  the  same 
compound  and  left  ready  for  the  tank  to  be  set  down  directly 
on  top. 

After  the  tank  has  been  properly  set  by  others,  suitable 
studding,  2-inch  x  a  dimension  equivalent  to  the  thickness  of 
the  first  course  of  corkboard  to  be  applied,  shall  be  set  36 
inches  apart  at  right  angles  against  the  sides  and  ends  of 
the  tank,  and  shall  be  carefully  anchored  by  dropping  them 
into  depressions  in  the  concrete  base  and  then  wedging  them 
under  and  securing  them  with  metal  clips  to  the  flange  at  the 
top  of  tank.  Between  the  studs,  one  layer  of  ...-inch  pure 
corkboard   shall   then   be   erected   with   all   joints   butted   and 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION        271 

sealed  with  hot  Asphalt  cement,  and  each  corkboard  secured 
to  the  studs  and  additionally  to  the  adjacent  corkboards  with 
galvanized  wire  nails.  To  the  first  course,  a  second  layer  of 
. .  .-inch  pure  corkboard  shall  be  erected  in  hot  Asphalt  cement 
with  all  joints  in  the  second  course  broken  with  respect  to 
all  joints  in  the  first  course  and  all  joints  butted  tight  and 
sealed  in  the  same  compound.  To  the  surface  of  the  insula- 
tion shall  then  be  applied  a  finish  as  selected. 

114. — Tanks. — Freezing   (continued). 

(34)  Double  layer  on  bottom,  both  in  Asphalt  cement ; 
single  layer  on  sides  and  ends  against  studs,  with  granulated 
cork  fill.' 


,_ __  STUDS 

:^:^-::,:r^-; 

■ .  %^ 

-^ 

^  .;-:--,.:-.^  .  , ^ 

5E.CTIONAL. 

PLAN 

1 

J. ;_• — 

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1              CORKl4>o}>R.O                 ; 

1 

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1  1           11 

;     ; 

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:; 

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^^ 

■*-■ 

ELL-E-VATIOM  CR055      SE.CTION 

FIG.    116.— TANKS;    FREEZING.      ARTICLE    114    (34). 

To  the  reasonably  smooth  and  clean  concrete  base,  of 
"'  dimensions  enough  wider  and  longer  than  the  size  of  the 
freezing  tank  sufificient  to  overlap  the  thickness  of  insulation 
on  ends  and  sides,  one  layer  of  .  .  .-inch  pure  corkboard  shall 
be  laid  down  in  hot  Asphalt  cement,  with  all  transverse  joints 
broken  and  all  joints  butted  tight.  To  the  first  course,  a  sec- 
ond layer  of  . .  .-inch  pure  corkboard  shall  be  laid  down  in  hot 
Asphalt  cement,  with  all  joints  in  the  second  course  broken 
!  with  respect  to  all  joints  in  the  first  course  and  all  joints 


272 


CORK  INSULATION 


butted  tight,  and  the  top  surface  then  flooded  with  the  same 
compound  and  left  ready  for  the  tank  to  be  set  down  directly 
on  top. 

After  the  tank  has  been  properly  set  by  others,  4-inch  x 
4-inch  studding  shall  be  set  on  18-inch  centers  at  right  angles 
against  the  sides  and  ends  of  the  tank,  and  shall  be  carefully 
anchored  by  dropping  them  into  depressions  in  the  concrete 
base  and  then  wedging  them  under  and  securing  them  with 
metal  clips  to  the  flange  at  the  top  of  tank.  Against  the  studs, 
one  layer  of  . .  .-inch  pure  corkboard  shall  be  secured  with  gal- 
vanized wire  nails,  with  all  joints  butted  and  sealed  with  hot 
Asphalt  cement.  The  space  between  the  studs,  the  sides  and 
ends  of  the  tank,  and  the  corkboard,  shall  then  be  filled  with 
regranulated  cork  well  tamped  in  place.  To  the  surface  of 
the  insulation  shall  then  be  applied  a  finish  as  selected. 

115. — Finish. — Walls  and  ceilings. 


Two     COATS 
OF      PORTL-AND 
CE.ME.NT     PUASTtR 
~^"  EACH. 


^ 

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f 

., 3COR 

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E- 

MARK 

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5 

' 



/I 

/I.     

CROSS 

SECTION 

FIG.    117.— FINISH; 


E1UE.VATION 
WALLS    AND    CEILINGS.      ARTICLE 


(35)     Portland  cement  plaster,  in  2  coats. 

To  the  exposed  surface  of  the  corkboard  insulation,  a  Port- 
land cement  plaster  finish  approximately  3^-inch  in  thickness 
shall  be  applied  in  two  coats.  The  first  coat  shall  be  approx- 
imately 34-inch  in  thickness,  rough  scratched,  and  mixed  one 
part  Portland  cement  to  two  parts  clean,  sharp  sand.    To  the 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION        273 

first  coat,  after  it  has  thoroughly  set,  a  second  coat,  mixed  in 
the  same  proportion,  shall  be  applied  approximately  ^-inch 
in  thickness,  and  troweled  to  a  hard,  smooth  finish.  The  sur- 
face shall  then  be  scored  in  ...-foot  squares  to  confine  any 
checking  and  cracking  of  the  plaster  to  such  score  marks. 

115. — Finish.- — Walls  and  ceilings    (continued). 


CORK  BOAR  D 


ACTORV  IRONED 


FINISH,  J-QI  NITS     SEAUELO 


ON4     MASTIC 


ELLEVATION 

FIG.    118.— FINISH;    WALLS    AND    CEILINGS.      ARTICLE    115    (36). 

(36)  Factory  ironed-on  mastic  finish,  joints  sealed. 
The  exposed  surface  of  the  corkboards,  used  on  the  second 

or  exposed  course  of  insulation,  shall  be  coated  to  a  thickness 
of  approximately  ^-inch  with  an  asphalt  mastic*  finish  ironed 
on  at  the  factory,  the  mastic  coating  having  beveled  (V) 
edges;  and  after  the  corkboard  is  erected,  all  joints  shall  be 
sealed  with  suitable  plastic  asphalt  mastic  put  carefully  in 
place  and  gone  over  with  the  point  of  a  hot  tool,  hot  enough 
to  melt  the  mastic  and  the  plastic  and  seal  the  joints  and 
render  them  tight. 

115. — Finish. — Walls  and  ceilings    (continued). 

(37)  Glazed  tile  or  brick,  in  Portland  cement. 

To  the  exposed  surface  of  the  corkboard  insulation,  a  Port- 
land cement  plaster  finish  approximately  ^-inch  in  thickness, 

*Each  manufacturer  presumably  follows  its  own  formula  for  the  particular  brand 
of  ironed-on  mastic  finish  offered,  and  its  probable  worth  in  service  must  be  judged 
accordingly. 


274 


CORK  INSULATION 


mixed   one   part   Portland   cement   to   two   parts   clean,   sharp 
sand,  shall  be  applied  in  one  coat,  floated  to  a  reasonably  true 


III'. 

Ii'i'  i.i.  M 


E.l_E.VATION 

QLA-ZLE-D     TILE.     OR     BRICK 

^"     PORT1.A.MD       CEME.MT      PLASTEt 

ROUan       SCRATCI-IE.D 

CORKBOA.RD 

PORTLAND       CtMENT     MORTAR 

CORKBOARD 

PORTL.AND      CE.ME.ISIT     MORTAR 


FIG.    119.— FINISH;    WALLS   AND    CEILINGS.      ARTICLE    115    (37). 

surface  and  left  rough  scratched.    A  glazed  tile  or  glass  brick 


finish,   as   specified 
tractor. 


hall    then   be   installed   by   another   con- 
Walls  and  ceilings    (continued). 


PUA3TIC 

MA^T/C     riniSH 
TRor/etrD    to 

tORK  BOARD    SURFACEi 

AT 

POINT     OF      Cf?£"CT(OM| 
LEFT       UN^COBeiO 


ELEVATION 

PI  AXTIC     MAATir    FlMI.Sh 

pnwTi  Hf^n CCMrMT    nnBTAR. 

FIG.    120.— FINISH;    WALLS    AND    CEILINGS.     ARTICLE    115    (m. 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION        275 

(38)     Emulsified  asphalt  plastic,  in  2  coats. 

The  surface  of  the  corkboards  to  receive  the  asphalt  plastic 
finish  shall  be  made  reasonably  even  and  true  by  trimming 
ofif  any  slight  projections. 

To  the  corkboard  surface  thus  prepared,  shall  be  applied 
two  coats  of  approved  Emulsified  Asphalt  Plastic.  The  first 
coat,  approximately  3/32-inch  in  thickness,  shall  be  applied 
under  a  wet  trowel,  care  being  taken  to  press  the  material 
firmly  into  the  surface  irregularities  of  the  corkboard.  When 
this  coat  has  set,  a  second  coat  shall  be  applied  under  a  wet 
trowel,  making  the  total  thickness  for  the  two  coats  not 
less  than  ^/^-inch.  The  second  coat  shall  be  troweled  smooth 
after  it  has  begun  to  set  but  before  it  has  hardened.  Its  sur- 
face shall  not  be  scored. 

116. — Finish. — Floors. 


\ '' 

V ► 

^ 

: 

^ 

i 

' 

f\  R5T        LAVELR   ^ 
OF       CORKBOARD 

)      ; 

'              IsE-COhslD         LAVE.R. 
\^        OF    CORKBOARD 

, 

^""'""'•""" 

A 

(,.       1        i  .. 

PLAN      OF      FLOOR 


PORTLAND      CEIMELNJT     FIKII5M 

CONCRE.TE 

CORKBOARD 


ASPHALT    CLMENT 


■....^.-.v-m 


a 


& 


Fl_OOR  SLAl 


CROSS      SECTION 
121.— FINISH;   FLOORS.     ARTICLE   116   (39). 


(39)     Concrete. 

A   ...-inch  concrete  wearing  floor  shall  be  laid  down  di- 
rectly on  top  of  the  asphalt  flooded  surface  of  the  corkboard, 


276 


CORK  INSULATION 


consisting  of  ...  inches  of  rough  concrete,  mixed  one  part 
Portland  cement  to  two  and  a  half  parts  clean,  sharp  sand  and 
five  parts  clean  gravel  or  crushed  stone,  well  tamped  in  place 
until  the  water  comes  to  the  surface,  and  then  followed  by  a 
1-inch  troweled  smooth  top  finish  composed  of  one  part  Port- 
land cement  and  one  part  clean,  sharp  sand.  The  concrete 
wearing  floor  shall  be  sloped  to  drain  as  desired. 

116. — Finish, — Floors  (continued). 

(40)     Wood. 

The   finished   wood  floor  shall   be   of  thoroughly   dry  and 


\^^         1/ 

--T— -i 

\    SLEE.P&R 

V              ^- 

\ 

___!_  _^ 

i 

FIRST         LA 
OF        CORKE 

|OF      C 

D       LAYEIR 
3  RKBOARD 

"T"\ 

' 

CL 

M 

1 
1 

PLAN       OF       FLOOR. 


^jtZ.      SLEE.PE.RS 
FLOORIMC 
CORKBOARD 


CROSS       SECTION 

FIG.    122.— FTNISn;    FLOORS.     ARTICLE    116    (40). 


seasoned  %-inch  T.  &  G.  ...  lumber,  laid  with  approximately 
1/32-inch  between  the  boards,  to  eliminate  as  much  as  pos- 
sible the  tendency  of  the  floor  to  expand  and  warp,  and  secret 
nailed  to  the  sleepers  that  were  provided  in  the  insulation 
underneath,  and  the  floor  left  perfectly  smooth  and  even. 


SPECIFICATIONS  FOR  CORKBOARD  ERECTION        277 


116. — Finish. — Floors  (continued). 
(41)     Galvanized  metal. 

Over  the  asphalt  flooded  surface  of  the  corkboard  on  the 
fioors  and  baffles  of  bunkers,  there  shall  be  installed  a  floor 


-FINISH;   FLOORS 


or  cover  of  .  .  ,  gauge  galvanized  iron.  The  metal  shall  extend 
over  all  edges  of  the  bunker  at  least  two  inches  and  be  se- 
curely anchored,  and  all  joints  and  nail  heads  in  the  finished 
work  shall  then  be  carefully  soldered. 


117. — Miscellaneous  Specifications. 


FIG.   124.— MISCELLANEOUS   SPECIFICATIONS.     ARTICLE   117   (42). 

(42)     Ends  of  beams  or  girders  extending  into  walls. 
All  beams  and  girders  extending  into  the  building  walls 
shall  be  insulated  on  the  ends,  tops  and  sides  with  one  layer 


278  CORK  INSULATION 

of  . .  .-inch  pure  corkboard  cut  accurately  and  joints  sealed 
tightly  with  hot  Asphalt  cement,  the  corkboard  extending  be- 
yond the  inside  face  of  the  wall  so  as  to  join  and  seal  with 
the  wall  insulation.  The  insulation  contractor  shall  furnish 
the  material  required  for  this  purpose,  but  the  installation 
shall  be  made  by  the  general  contractor. 

117. — Miscellaneous  Specifications  (continued). 

(43)  Rat  proofing. 

As  a  barrier  against  rats  and  mice  entering  this  cold  stor- 
age room,  there  shall  be  installed  over  all  areas  of  the  room 
and  securely  stapled  in  place,  with  all  joints  carefully  butted 
or  lapped,  galvanized  wire  square-mesh  screen,  No.  18  gauge,  3 
mesh  (1/3-inch).  The  screen  shall  be  located  as  near  as  pos- 
sible to  the  point  of  expected  attack,  that  is,  the  screen  shall 
be  laid  across  ceiling  joists  and  wall  studding  before  the 
sheathing  is  applied,  fastened  to  the  surface  of  soft  brick  or 
laid  down  over  w^ood  floor  before  the  first  layer  of  insulation 
is  applied,  and  similarly  used  elsewhere  as  required. 

117. — Miscellaneous  Specifications  (continued). 

(44)  Portland  cement  mortar.  ! 
The    Portland   cement   mortar    (not   the    Portland   cement    ! 

plaster)  used  in  connection  with  the  corkboard  insulation  on 

walls  and  partitions   shall   be   mixed   in   the   proportion   of   one  ; 
part  Portland  cement  to  two  parts  clean,  sharp  sand. 

The  Portland  cement  mortar  used  in  connection  with  the  ' 

corkboard  insulation  on  ceilings  shall  be  mixed  in  the  propor-  | 

tion   of  one   part   Portland   cement   to   one   part   clean,    sharp  ' 

sand.  j 

(45)  Asphalt  cement. 

Note:  See  specification  given  in  Article  100,  under  head  i 
ing  entitled,  ''Specification  for  Asphalt  cement  for  cold  stor-  : 
age  insulation."  i 

(46)  Asphalt  primer. 

Note:  See  specification  given  in  Article  100,  under  head- 
ing entitled,  "Asphalt  primer  for  use  with  Asphalt  cement." 


CHAPTER  XIV. 

COMPLETE  DIRECTIONS  FOR  THE  PROPER  APPLI- 
CATION OF  CORKBOARD  INSULATION. 

118. — General  Instructions  and  Equipment. — For  many 
years  it  was  considered  necessary,  or  at  least  highly  desirable, 
that  all  corkboard  surfaces  to  be  erected  in  Portland  cement 
mortar  and  all  corkboard  surfaces  to  be  finished  with  Port- 
land cement  plaster,  should  be  scored  on  the  side  against 
which  the  mortar  or  plaster  was  specified  to  be  applied.  This 
scoring  had  to  be  done  at  the  factory  and  consisted  of  several 
parallel  saw  grooves  running  the  length  of  the  corkboards, 
and  which  were  put  there  as  a  key  or  bond  for  the  cement. 
Experience  has  demonstrated,  however,  that  the  plain  surface 
of  corkboard  is  of  such  character  as  to  permit  an  intimate  and 
satisfactory  bond  with  Portland  cement,  as  with  Asphalt  ce- 
ment, and  score  marks  are  no  longer  considered  essential. 
The  plain  corkboard  may  be  scored  on  the  job,  if  scoring  is 
preferred,  before  being  erected  in  Portland  cement  mortar, 
by  roughening  the  surface  slightly  with  any  pronged  tool, 
such  as  a  few  wire  nails  driven  through  a  piece  of  wood.  If 
it  is  desired  to  roughen  the  surface  to  receive  Portland  cement 
plaster,  then  the  work  is  done  after  the  corkboard  has  been 
put  in  place  and  just  before  the  first  coat  of  plaster  is  applied. 

The  Portland  cement  mortar,  in  which  corkboard  is  fre- 
quently erected  to  masonry  walls,  and  the  like,  should  be  pre- 
pared by  mixing*  one  part  (by  volume)  of  any  standard  grade 
of  Portland  cement  with  two  parts  of  clean,  sharp  sand.  Be 
sure  the  sand  is  clean,  and  be  sure  that  it  is  sharp.  It  will 
require  5.0  barrels  of  Portland  cement*  and  2.1  cubic  yards  of 


*The  Portland  Cement  Association,  33  West  Grand  Avenue,  Chicago,  Illinois,  with 
branches  in  many  cities,  gladly  furnish  complete  data  relating  to  the  proper  mixing  of 
Portland  cement  for  any  purpose.     Also  see  Appendix  of  this  text. 

279 


280 


CORK  INSULATION 


sand*  for  each  thousand  square  feet  of  surface.  Do  not  mix 
too  much  mortar  at  a  time,  make  it  fairly  stifif,  and  do  not 
add  any  lime. 

Portland  cement  mortar,  or  "backing,"  should  be  uniformly 
one-half  inch  in  thickness  over  the  whole  surface  of  the  cork- 
boards  and  none  should  be  allowed  on  the  sides  and  ends. 
This  cement  backing  is  never  applied  directly  to  the  area  to 


MG.  1-5.  CORKBOARD  KRECTED  TU  CONCRETE  WAELS  AXD  COLL'.MXS 
IN  PORTLAND  CEMENT  MORTAR.— xNOTE  THE  SIMPLE  MORTARBOARD 
AND  HOPPER  DEVICE  FOR  APPLICATION  OF  THE  "BACKING"  DE- 
SCRIBED   IN   THE   TEXT. 


be  insulated,  as  some  might  suppose,  but  to  the  surfaces  of  the 
individual  corkboards  before  they  are  set  in  place.  To  facili- 
tate the  application  of  the  cement  backing  to  the  corkboards, 
a  mortar  board  about  4  feet  square  is  equipped  with  a  simple 
runway  and  hopper  attachment  that  is  entirely  practical  and 
very  satisfactory.  Across  the  top  of  the  mortar  board  nail 
two  strips  parallel  to  each  other  and  exactly  12  inches  apart, 

*1  barrel  cement  =  4  sacks  =  4  cubic  feet  =  400  pounds;  1  cubic  yard  sand  = 
approximately  2,400  pounds — based  on  tables  in  "Concrete,  Plain  and  Re'nforced,"  by 
Taylor  and  Thompson. 


DIRECTIONS  FOR  CORKBOARD  ERECTION 


281 


so  that  one  standard  sheet  of  corkboard  (12  inches  wide  x 
36  inches  long)  may  be  laid  down  between  them.  Make  the 
height  of  these  strips  one-half  inch  more  than  the  thickness 
of  the  corkboards  to  be  coated.  Construct  a  simple  wooden 
hopper  about  two  feet  high,  having  an  opening  at  the  top 
about  2  feet  x  2  feet  and  one  at  the  bottom  exactly  12  inches 
by   12  inches.     Mount  the  hopper  on  the  two  strips  so  that  a 


FIG.  126.— ERECTING  CORKBOARD  IX  ASPHALT  CEMENT  TO  ASPHALT 
PRIMED  CONCRET-E  WALL  SURFACES.— NOTE  THE  ASPHALT  PAX 
AXD  OIL  STONE  ARRAXGEMEXT  FOR  HOLDIXG  ODORLESS  ASPHALT 
AT   THE   CORRECT  TEMPERATURE  AT  POIXT   OF   ERECTION. 


corkboard  can  be  pushed  through  the  runway  (formed  by  the 
two  strips)  and  under  the  hopper.  Then  fill  the  hopper  with 
Portland  cement  mortar;  and  by  pushing  one  board  through 
ahead  of  another,  butted  end  to  end,  the  individual  boards  are 
uniformly  coated  to  a  thickness  of  one-half  inch  and  without 
the  liklihood  of  the  mortar  getting  on  the  sides  and  ends  of 
the  corkboards. 


282  CORK  INSULATION 

To  prepare  Asphalt  cement  for  use  with  corkboard  to  walls 
and  ceilings  requires  a  large  kettle,  several  small  kettles  and 
an  equal  number  of  gasoline  torches,  and  several  buckets. 
Set  up  the  large  kettle  outside  the  building  and  melt  down 
sufficient  Asphalt  cement,  or  odorless  asphalt,  computed  at 
three-quarters  of  a  pound  for  each  square  foot  of  corkboard 
surface  to  be  coated,  using  wood  as  fuel  under  the  kettle,  and 
the  fire  protected  from  possible  wind  by  a  sheet-iron  shield. 
Do  not  overheat  the  asphalt.  Transfer  the  molten  asphalt  in 
buckets  to  the  small  kettles,  or  pans,  located  close  to  where 
the  corkboard  is  being  erected.  The  pans  should  be  about  18 
inches  wide,  42  inches  long  and  8  inches  deep,  should  be 
rigidly  constructed,  and  should  be  kept  hot  by  the  gasoline 
torches.*  To  the  molten  asphalt  in  these  pans,  add  approx- 
imately 8  per  cent,  (by  weight)  of  cork  dust,  or  cork  flour, 
and  stir  in  thoroughly.  The  admixture  of  the  cork  dust 
stiffens  up  the  molten  asphalt  just  enough  so  that  the  proper 
quantity  clings  to  the  corkboards  when  dipped. 

To  prepare  Asphalt  cement  for  use  with  corkboard  on 
floors  and  bottoms  of  freezing  tanks,  proceed  as  outlined  in 
the  foregoing  paragraph,  except  no  pans  are  ordinarily  needed 
and  no  cork  dust  is  mixed  with  the  molten  asphalt. 

Ordinary  wire  nails  should  never  be  used  in  erecting  cork- 
board insulation,  because  they  will  soon  rust  away,  although 
they  are  sometimes  employed  by  careless  and  disinterested 
erectors.  Galvanised  wire  nails  having  large  heads  and  of 
proper  length  should  always  be  used  where  specified,  but  do 
not  use  galvanized  wire  nails  where  wood  skezvers  are  speci- 
fied and  can  be  employed  instead.  Wood,  even  hard  hickory, 
is  a  far  better  thermal  insulator  than  metal,  and  consequently 
galvanized  wire  nails  should  never  be  used  where  wood 
skewers  will  serve  the  purpose,  for  there  is  always  danger  of 
frost  following  in  along  nails  or  forming  on  wall  finishes  over 
nail  heads  underneath.  Hickory  skewers  should  be  used  in  i 
preference  to  softer  woods,  to  diminish  the  chances  for  damage  ■ 
to  the  hands  of  workmen  from  splintering  and  breaking  of  the 
skewers  when  being  driven  into  the  insulation. 

*CAUTION — Gasoline  torches  have  been  known  to  explode  if  not  properly  con- 
structed, not  kept  in  proper  condition,  or  not  properly  operated.  Charcoal  pots  are 
less  applicable,  but  safer.  See  Appendix  for  description  of  Oil-Burning  Cork  Dipping 
Pan. 


DIRECTIONS  FOR  CORKBOARD  ERECTION  283 

If  masonry  surfaces  are  to  be  primed  with  Asphalt  primer 
before  the  corkboard  is  applied  in  Asphalt  cement,  the  work 
should  be  done  with  an  air-gun,  if  possible.  The  complete 
equipment  for  such  application  consists  of  a  suitable  air-gun 
of  approved  make  and  the  necessary  supply  of  compressed 
air. 

Extension  cords,  electric  light  guards,  sand  screens,  metal 
mortar  boxes,  hods,  hoes,  shovels,  trowels,  rope  and  tackle, 
hand  saws,  hatchets,  hammers,  salamanders,  metal  w^heelbar- 
rows,  water  buckets,  rubber  hose,  big  asphalt  kettle  on  wheels 
with  firebox  and  stack,  these  and  possibly  other  utensils  con- 
stitute some  of  the  additional  equipment  that  may  be  required 
to  properly  handle  a  corkboard  insulation  job. 

Where  cold  storage  doors  are  to  be  installed,  it  is  neces- 
sary that  the  outside  dimensions  of  the  door  frames  be  known 
in  advance,  so  that  if  necessary  or  desirable  the  door  bucks 
and  lintels  may  be  properly  placed  in  the  line  of  insulated 
walls  or  partitions  in  advance  of  the  actual  arrival,  or  of 
the  uncrating,  of  the  door  equipment. 

Unnecessary  and  sometimes  very  expensive  delays  in  the 
prosecution  and  completion  of  a  given  job  of  cork  insulation 
may  be  brought  about  through  failure  of  the  job  superintend- 
ent to  check  first  of  all  the  actual  size  of  rooms  and  tanks  to 
be  insulated  against  the  measurements  as  originally  planned, 
and  then,  as  the  materials,  supplies  and  equipment  are  deliv- 
ered, to  check  them  carefully  against  the  requirements  of 
the  work.  The  superintendent  must,  in  a  word,  anticipate  his 
needs  well  and  sufficiently  in  advance. 

119. — First  Layer  Corkboard,  Against  Masonry  Walls,  in 
Portland  Cement  Mortar. — See  that  the  walls  present  a  rea- 
•  sonably  smooth  and  level  surface,  remove  all  dirt,  plaster, 
loose  mortar,  whitewash,  paint,  or  other  foreign  material,  and 
if  the  walls  are  very  smooth  concrete,  roughen  them  by  hack- 
ing the  surface  with  a  hatchet  or  hacking  hammer,  or  arrange 
to  have  these  several  items  taken  care  of  by  those  responsible 
for  such  preliminary  work,  before  making  preparations  to 
erect  corkboard  to  masonry  walls  in  Portland  cement  mortar. 
Now  see  that  the  floor  at  the  base  of  the  wall  is  free  from 
obstruction,  and  is  level;  because  the  first  row  of  corkboards 


284  CORK  INSULATION 

must  be  applied  to  the  wall  at  the  floor,  on  a  level  line,  so 
that  the  corkboards  on  the  entire  wall  area  are  kept  in  perfect 
alignment  and  all  vertical  and  transverse  joints  in  the  upper 
rows  are  made  to  fit  close  and  tight. 

Prepare  suitable  Portland  cement  mortar  in  reasonable 
quantity,  sprinkle  the  wall  to  be  insulated  with  clean  water, 
coat  one  side  of  each  corkboard  with  a  half-inch  of  Portland 
cement  mortar.  1\\  the  l:()])per  method.  ]-nt  each  in  prnner  posi- 


FIG.     127.— ERECTING     FIRST     LAYER     CORXBOARD     AGAIXST     iMASOXRY 
WALL   IN    PORTLAND    CEMENT    MORTAR. 

tion  against  the  wall,  slightly  press  into  place  and  hold  for  a 
few  moments  until  the  mortar  begins  to  set.  Keep  cement 
backing  oflf  edges  of  corkboards.  Do  not  "vacuum  cup"  the 
backing  before  setting  the  corkboards,  by  hollowing  out  the 
mortar  with  the  point  of  a  trowel,  because  it  is  impossible 
to  spread  out  the  mortar  again  in  setting  the  corkboards,  and 
air  pockets  behind  insulation,  with  disastrous  results,  will  be 
inevitable. 

Cut  a  corkboard  half-length  and  with  it  start  setting  the 
second  row  on  top  of  the  first,  thus  breaking  vertical  joints. 
As  each  corkboard  is  set,  butt  it  tightly  at  all  points  of  con- 
tact against  the  adjoining  boards,  but  do  not  loosen  boards 
already  in  position.  Join  the  wall  insulation  tightly  with  the 
ceiling,  cutting  pieces  of  corkboard  neatly  to  fit  and  never 
using  Portland  cement  mortar  to  fill  in  openings  between 
corkboards  or  pieces  of  corkboard. 

Give  the  cement  backing  ample  time  to  set,  say  48  hours. 


DIRECTIONS  FOR  CORKBOARD  ERECTION  285 

betore  erecting  another  layer  of  corkboard  against  the  first, 
or  before  applying  a  finish  over  the  insulation. 

120. — First  Layer  Corkboard,  Against  Masonry  Walls,  in 
Asphalt  Cement. — See  that  the  walls  present  a  reasonably 
smooth  and  level  surface,  remove  all  dirt,  plaster,  loose  mortar, 
whitewash,  paint,  or  other  foreign  material,  or  arrange  to  have 
these  several  items  taken  care  of  by  those  responsible  for  such 
preliminary  work,  before  making  preparations  to  erect  cork- 
board to  masonry  walls  in  Asphalt  cement. 


FIG.  128.— ERECTING  FIRST  LAYER  CORKBOARD  AGAINST  CONCRETE 
WALLS,  COLUMNS  AND  COLUMN  CAPS  IN  ASPHALT  CEMENT  TO 
SUITABLY  PRIMED  SURFACES.— NOTE  PRIMED  BUT  UNINSULATED 
WALL   AND  COLUMN   SECTION   AT  TOP  LEFT. 

With  suitable  Asphalt  primer  and  proper  air-gun  equip- 
ment, apply  evenly  under  a  minimum  air  pressure  of  50  pounds, 
to  the  entire  masonry  wall  surfaces  to  be  insulated,  two  uni- 
form, continuous  coats  of  the  priming  liquid,  using  approx- 
imately 1  gallon  per  75  square  feet  for  brick  or  per  100  square 
feet  for  concrete  surfaces  for  the  first  coat,  and  1  gallon  per 
125  square  feet  for  brick  or  concrete  for  the  second  coat.  If 
the  Asphalt  primer  thickens  because  of  exposure  to  the  air, 
or  during  very  cold  weather,  it  may  be  thinned  with  suitable 
solvent  to  permit  an  even  flow  through  the  air-gun  nozzle. 
The  first  coat  is  to  become  hand-dry  before  the  second  is  ap- 


286 


CORK  INSULATION 


plied,   and   the    second    is    to    become    hand-dry    before   cork- 
board  is  applied. 

See  that  the  floor  at  the  base  of  the  wall  is  free  from  ob- 
struction, and  is  level ;  because  the  first  row  of  corkboards 
must  be  applied  to  the  wall  at  the  floor,  on  a  level  line,  so  that 
the  corkboards  on  the  entire  wall  area  are  kept  in  perfect  align- 
ment and  all  vertical  and  transverse  joints  in  the  upper  rows 
are  made  to  fit  close  and  are  sealed  tit^ht. 


FIG.  129.— ERECTING  DOUBLE  LAYER  CORKBOARD  TO  ASPHALT  PRIMED 
CONCRETE  WALL  SURFACE  IN  ASPHALT  CEMENT,  AS  CONTINUOUS 
INSULATION  THROUGH  CONCRETE  FLOOR  SLAB. 


Prepare  suitable  Asphalt  cement  in  reasonable  quantity, 
distribute  it  to  heated  pans,  add  the  proper  proportion  of 
cork  dust  and  mix,  dip  one  flat  side,  one  end  and  one  edge  of 
each  corkboard  in  the  molten  material,  put  the  boards  in 
proper  position  against  the  wall,  slightly  press  into  place  and 
hold  for  a  few  moments  until  the  Asphalt  cement  begins  to 
cool. 


DIRECTIONS  FOR  CORKBOARD  ERECTION  287 

Cut  a  corkboard  half-length  and  with  it  start  setting  the 
second  row  on  top  of  the  first,  thus  breaking  vertical  joints. 
As  each  corkboard  is  set,  butt  and  seal  it  tightly  at  all  points 
of  contact  against  the  adjoining  boards.  Join  and  seal  the 
wall  insulation  tightly  with  the  ceiling,  cutting  pieces  of  cork- 
board neatly  to  fit. 

Give  the  Asphalt  cement  ample  time  to  cool  and  set,  say  12 
hours,  before  erecting  another  layer  of  corkboard  against  the 
first,  or  before  applying  a  finish  over  the  insulation. 

121. — First  Layer  Corkboard,  Against  Wood  Walls,  in 
Asphalt  Cement. — See  that  the  walls  present  a  smooth,  con- 
tinuous, solid  surface,  free  from  open  cracks  and  loose  or 
warped  boards,  remove  all  dirt,  plaster,  loose  mortar,  paper  or 
other  foreign  material,  or  arrange  to  have  these  several  items 
taken  care  of  by  those  responsible  for  such  preliminary  work, 
before  making  preparations  to  erect  corkboard  to  wood  walls 
in  Asphalt  cement. 

See  that  the  floor  at  the  base  of  the  wall  is  free  from  ob- 
struction, and  is  level ;  because  the  first  row  of  corkboards 
must  be  applied  to  the  wall  at  the  floor,  on  a  level  line,  so 
that  the  corkboards  on  the  entire  wall  area  are  kept  in  per- 
fect alignment  and  all  vertical  and  transverse  joints  in  the 
upper  rows  are  made  to  fit  close  and  are  sealed  tight. 

Prepare  suitable  Asphalt  cement  in  reasonable  quantity, 
distribute  it  to  heated  pans,  add  the  proper  proportion  of 
cork  dust  and  mix,  dip  one  flat  side,  one  end  and  one  edge 
of  each  corkboard  in  the  molten  material,  put  the  boards  in 
proper  position  against  the  wall,  slightly  press  into  place  and 
securely  nail  in  position  to  sheathing  with  galvanized  wire 
nails  driven  obliquely,  two  nails  per  square  foot. 
'^  Cut  a  corkboard  half-length  and  with  it  start  setting  the 
second  row  on  top  of  the  first,  thus  breaking  vertical  joints. 
As  each  corkboard  is  set,  butt  and  seal  it  tightly  at  all  points 
of  contact  against  the  adjoining  boards.  Join  and  seal  the 
wall  insulation  tightly  with  the  ceiling,  cutting  pieces  of 
corkboard  neatly  to  fit. 

Give  the  Asphalt  cement  ample  time  to  cool  and  set,  say 
12  hours,  before  erecting  another  layer  of  corkboard  against 
the  first,  or  before  applying  a  finish  over  the  insulation. 


288  CORK  INSULATION 

122. — Second  Layer  Corkboard,  Against  First  Layer  on 
Walls,  in  Portland  Cement  Mortar. — See  that  the  first  layer  of 
corkboard  on  the  walls  is  solidly  attached,  and  presents  a  rea- 
sonably smooth  and  level  surface,*  then  remove  all  dust, 
dirt  or  loose  mortar,  before  making  preparations  to  erect  a 
second  layer  of  corkboard  in  Portland  cement  mortar. 

Now  see  that  the  floor  at  the  base  of  the  wall  is  free  from 
obstruction,  and  is  level ;  because  the  first  row  of  corkboards 
in  the  second  layer  must  be  applied  to  the  first  layer  at  the 
floor,  on  a  level  line,  so  that  the  corkboards  on  the  entire 
second  layer  are  kept  in  perfect  alignment  and  all  vertical  and 
transverse  joints  in  the  upper  rows  are  made  to  fit  close  and 
tight. 

Prepare  suitable  Portland  cement  mortar  in  reasonable 
quantity,  saw  sufficient  corkboards  lengthwise  down  the  center 
so  as  to  have  enough  half-width  pieces  to  make  one  row  around 
the  room,  coat  the  half-width  corkboards  on  one  side  with 
a  half-inch  of  Portland  cement  mortar,  cut  a  piece  6  inches 
wide  and  27  inches  long  and  with  it  start  putting  the  half- 
width  pieces  of  corkboard  in  proper  position  against  the  first 
layer  of  insulation,  slightly  press  into  place  and  additionally 
secure  with  wood  skewers  driven  obliquely,  two  skewers 
per  square  foot. 

Then  start  with  a  full-width  and  9-inch  long  piece  of 
corkboard  and  set  the  second  row  of  full-size  corkboards  on 
top  of  the  first  row,  thus  breaking  vertical  joints  in  the  sec- 
ond layer,  and  all  joints  in  the  second  layer  with  respect  to 
all  joints  in  the  first  layer.  As  each  corkboard  is  set,  butt  it 
tightly  at  all  points  of  contact  against  the  adjacent  boards 
and  additionally  secure  to  the  first  layer  with  wood  skewers 
driven  obliquely,  two  skewers  per  square  foot.  Join  the  wall 
insulation  tightly  with  the  ceiling,  cutting  pieces  of  cork- 
board neatly  to  fit  and  never  use  Portland  cement  mortar 
to  fill  in  openings  between  corkboards  or  pieces  of  corkboard. 

Give  the  cement  backing  ample  time  to  set,  say  48  hours, 
before  applying  a  finish  over  the  insulation. 


*If  necessary,  cut  off  any  protruding  corners  or  edges  of  corkboard  with  a  suitable 
tool. 


DIRECTIONS  FOR  CORKBOARD  ERECTION  289 

123. — Second  Layer  Corkboard,  Against  First  Layer  on 
Walls,  in  Asphalt  Cement. — See  that  the  first  layer  of  cork- 
board  on  the  walls  is  solidly  attached,  and  presents  a  rea- 
sonably smooth  and  level  surface,*  and  then  remove  all  dust, 
dirt  or  loose  mortar,  before  making  preparations  to  erect  a 
second  layer  of  corkboard  in  Asphalt  cement. 

Now  see  that  the  floor  at  the  base  of  the  wall  is  free  from 
obstruction,  and  is  level ;  because  the  first  row  of  corkboards 
in  the  second  layer  must  be  applied  to  the  first  layer  at  the 
floor,  on  a  level  line,  so  that  the  corkboards  on  the  entire 
second  layer  are  kept  in  perfect  alignment  and  all  vertical 
and  transverse  joints  in  the  upper  rows  are  made  to  fit  close 
and  are  sealed  tight. 

Prepare  suitable  Asphalt  cement  in  reasonable  quantity, 
distribute  it  to  heated  pans,  add  the  proper  proportion  of  cork 
dust  and  mix.  Saw  sufficient  corkboards  lengthwise  down 
the  center  so  as  to  have  enough  half-width  pieces  to  make 
one  row  around  the  room,  cut  a  piece  6  inches  wide  and  27 
inches  long  and  with  it  start  putting  the  half-width  pieces 
of  corkboard  in  proper  position  against  the  first  layer  of  in- 
sulation, first  dipping  one  flat  side,  one  end  and  one  edge 
of  each  piece  in  the  molten  material,  slightly  pressing  into 
place  and  additionally  securing  with  galvanized  wire  nails  or 
wood  skewers,  as  specified,  driven  obliquely,  two  per  square 
foot. 

Then  start  wuth  a  full-width  and  9-inch  long  piece  of  cork- 
board and  set  the  second  row  of  full-size  corkboards  on  top 
of  the  first  row,  thus  breaking  vertical  joints  in  the  second 
layer,  and  all  joints  in  the  second  layer  with  respect  to  all 
joints  in  the  first  layer.  As  each  corkboard  is  set,  butt  it 
tightly  at  all  points  of  contact  against  the  adjacent  boards 
and  additionally  secure  to  the  first  layer  with  galvanized 
wire  nails  or  wood  skewers,  as  specified,  driven  obliquely, 
two  per  square  foot.  Join  and  seal  the  wall  insulation  tightly 
with  the  ceiling,  cutting  pieces  of  corkboard  neatly  to  fit. 

Give  the  asphalt  cement  ample  time  to  cool  and  set,  say 
12  hours,  before  applying  a  finish  over  the  insulation. 

*If  necessary,  cut  off  anv  protruding  corners  or  edge  of  corkboard  with  a  suitable 
tool. 


290 


CORK  INSULATION 


124. — First  Layer  Corkboard,  to  Concrete  Ceilings,  in  Port- 
land Cement  Mortar. — See  that  the  ceiling  presents  a  reason- 
ably smooth  and  level  surface,  remove  all  dirt,  plaster,  loose 
mortar,  whitewash,  paint,  or  other  foreign  material,  and  if 
the  ceiling  is  very  smooth  concrete,  roughen  it  by  hacking  the 
surface  with  a  hatchet  or  hacking  hammer,  or  arrange  to  have 
these  several  items  taken  care  of  by  those  responsible  for  such 
preliminary  work,  before  making  preparations  to  erect  cork- 
hoard  to  ceiling  in  Portland  cement  mortar. 


FIG.  130.— ERECTING  FIRST  LAVEK  CORKBOARD  TO  CONCRETE  CEILING  I 
IN  PORTLAND  CEMENT  MORTAR.— NOTE  METHOD  OF  PROPPING  . 
UNTIL  CEMENT   SETS. 

Prepare  suitable  Portland  cement  mortar  in  reasonable  i 
quantity,  sprinkle  the  ceiling  to  be  insulated  with  clean  water, 
coat  one  side  of  each  corkboard  with  a  half-inch  of  Portland  | 
cement  mortar,  by  the  hopper  method,  put  each  in  proper  i 
position  against  the  ceiling,  press  firmly  into  place  and  prop  I 
until  the  cement  sets.  Keep  cement  backing  ofif  edges  of  cork- 
boards.  Do  not  "vacuum  cup"  the  backing  before  setting  the  ■ 
corkboards,  by  hollowing  out  the  mortar  with  the  point  of  } 
a  trowel,  because  it  is  impossible  to  spread  out  the  mortar  ' 
again  in  setting  the  corkboards,  and  air  pockets  behind  in-  \ 
sulation,  with  disastrous  results,  will  be  inevitable. 

Apply  the  first  row  of  corkboards  against  the  ceiling  along 
one  side  of  the  room,  in  a  straight  line.  Keep  the  sheets  in 
perfect  alignment,  so  that  the  joints  in  the  rows  to  follow 
may  fit  close  and  tight. 

Cut  a  corkboard  to  half-length  and  with  it  start  setting 
and  propping  a  second  row  of  full-size  corkboards  adjacent 


i 


DIRECTIONS  FOR  CORKBOARD  ERECTION 


291 


to  the  first  row,  thus  breaking  transverse  joints.  As  each 
corkboard  is  set,  butt  it  tightly  at  all  points  of  contact  against 
the  adjacent  boards,  but  do  not  loosen  boards  already  in 
position.  Join  the  ceiling  insulation  tightly  with  the  wall, 
cutting  pieces  of  corkboard  neatly  to  fit  and  never  using  Port- 
land cement  mortar  to  fill  in  openings  between  corkboards 
or  pieces  of  corkboard. 

Give  the  cement  backing  ample  time  to  set,  at  least  48 
hours,  before  erecting  another  layer  of  corkboard  against 
the  first,  or  before  applying  a  finish  over  the  insulation. 

125. — First  Layer  Corkboard,  in  Concrete  Ceiling  Forms. — 

See  that  the  wooden  forms  for  the  concrete  ceiling  slab  have 


^s^ 


FIG.     131.— PL..\C1.NG     FIRST     LAYER     CORKBOARD     IN     CEILING     FORMS 
BEFORE  CONCRETE  IS  POURED. 


been  lowered  the  proper  distance  to  allow  for  the  thickness  of 
the  layer*  of  corkboard  specified  to  be  placed  in  forms,  and  see 


'Never  put  two  layers  of  corkboard  in  ceiling  forms. 


292  CORK  INSULATION 

that  the  forms  are  reasonably  even.     Lay  down  the  first  row  '. 

of  corkboards  on  the  forms,  along  one  side  of  the  ceiling  area,  ; 

in  a  straight  line.    Keep  the  corkboards  in  perfect  alignment,  i 

so  that  the  joints  in  the  rows  to  follow  may  fit  close  and  tight.  I 

If  the  surface  of  the  forms  should  be  slightly  uneven,  se-  j 

cure  the  corkboards  to  the  forms  with  a  few  headless  finishing  I 

nails,  which  will  easily  pull  out  of  the  corkboard  when  the  j 

forms  are  removed.     Break  all  joints  between  the  different  : 

rows,  by  starting  alternate  rows  with  half-length  boards,  and  i 

see  that  all  joints  are  butted  close  and  made  tight,  so  that  j 

none  of  the  concrete  can  run  down  between  the  corkboards  I 

and  pieces  of  corkboard  when  the  concrete  is  poured.     When  ! 
the  opposite  end  and  the  opposite  side  of  the  ceiling  area  is 

reached,  cut  pieces  of  corkboard  neatly  to  fit  the  outline  of  ■ 

the  forms.  ! 

Drive  three  galvanized  wire  nails  per  square  foot  obliquely  j 

into  the  corkboard  and  leave  the  heads  protruding  about  V/2  ] 

inches  to  afiford  an  additional  key  for  the  concrete,  and  leave  , 

the  insulation  in  readiness  for  the  concrete  contractor  to  pour  1 

the  ceiling  slab.  ! 

After  forms  have  been  removed,  permit  this  layer  of  cork- 
board on  underside  of  concrete  ceiling  to  dry  out  thoroughly,  j 
not  less  than  an  additional  48  hours,  before  erecting  another  ' 
layer  of  corkboard  against  the  first,  or  before  applying  a  finish  ; 
over  the  insulation. 

126. — First  Layer  Corkboard,  to  Wood  Ceiling,  in  Asphalt 
Cement. — See  that  the  ceiling  presents  a  smooth,  continuous, 
solid  surface,  free  from  open  cracks  and  loose  or  warped 
boards,  remove  all  dirt,  plaster,  paper,  or  other  foreign  mate- 
rial, or  arrange  to  have  these  several  items  taken  care  of  by 
those  responsible  for  such  preliminary  work,  before  making 
preparations  to  erect  corkboard  to  wood  ceiling  in  Asphalt 
cement. 

Prepare  suitable  Asphalt  cement  in  reasonable  quantity, 
distribute  it  to  heated  pans,  add  the  proper  proportion  of 
cork  dust  and  mix,  dip  one  flat  side,  one  end  and  one  edge  of 
each  corkboard  in  the  molten  material,  lay  up  the  first  row 
of  corkboards  to  the  ceiling  surface  and  against  the  edge  of 


DIRECTIONS  FOR  CORKBOARD  ERECTION  293 

the  wall,  in  a  straight  line,  slightly  press  the  corkboards  into 
place  and  securely  nail  in  position  to  sheathing  with  gal- 
vanized wire  nails  driven  obliquely,  three  nails  per  square 
foot.  Keep  the  corkboards  in  perfect  alignment,  so  that  the 
joints  in  the  rows  to  follow  may  fit  close  and  seal  tight. 

Break  all  joints  between  the  different  rows,  by  starting 
alternate  rows  with  half-length  boards,  and  see  that  all  joints 
are  butted  close  and  sealed  tight.  When  the  opposite  end 
and  the  opposite  side  of  the  ceiling  area  is  reached,  cut  pieces 
of  corkboard  neatly  to  fit  and  seal  with  the  wall  lines  of  the 
room. 

Give  the  Asphalt  cement  ample  time  to  cool  and  set,  say 
12  hours,  before  erecting  another  layer  of  corkboard  against 
the  first,  or  before  applying  a  finish  over  the  insulation. 

127. — Second  Layer  Corkboard,  to  First  Layer  on  Ceiling, 
in  Portland  Cement  Mortar. — See  that  the  first  layer  of  cork- 
board on  the  ceiling  is  solidly  attached,  and  presents  a  reason- 
ably smooth  and  level  surface,*  and  then  remove  all  dust,  dirt, 
or  other  foreign  material,  before  making  preparations  to  erect 
a  second  layer  of  corkboard  in  Portland  cement  mortar. 

Saw  sufficient  corkboards  lengthwise  down  the  center  so 
as  to  have  enough  half-width  pieces  to  make  one  row  along 
one  side  of  the  ceiling.  Cut  a  piece  6  inches  wide  and  27  inches 
long  with  which  to  start  setting  the  half-width  pieces  in  proper 
position  to  the  ceiling  area,  in  a  straight  line,  against  the 
edge  of  the  wall. 

Prepare  suitable  Portland  cement  mortar  in  reasonable 
quantity,  coat  one  side  of  each  piece  of  corkboard  with  a 
half-inch  of  Portland  cement  mortar,  put  each  in  proper 
position  against  the  ceiling,  press  firmly  into  place  and  addi- 
tionally secure  with  galvanized  wire  nails  or  wood  skewers, 
as  specified,  driven  obliquely,  three  per  square  foot.  Keep 
the  pieces  of  corkboard  in  perfect  alignment,  so  that  the  joints 
in  the  rows  to  follow  may  fit  close  and  seal  tight. 

Then  start  with  a  full-width  and  9-inch  long  piece  of  cork- 
board and  set  the  second  row  of  full-size  corkboards  adjacent 
to  the  first  row,  thus  breaking  all  joints  in  the  second  layer, 

*If  necessary,  cut  off  any  protruding  corners  or  edges  of  corkboard  with  a  suitable 


294  CORK  INSULATION 

and  all  joints  in  the  second  layer  with  respect  to  all  joints 
in  the  first  layer.  As  each  corkboard  is  laid  up,  butt  it  tightly 
at  all  points  of  contact  against  the  adjacent  boards,  and  addi- 
tionally secure  to  the  first  layer  with  galvanized  wire  nails  or 
wood  skewers,  as  specified,  driven  obliquely,  three  per 
square  foot.  Join  the  second  layer  of  ceiling  insulation  tightly 
with  the  opposite  wall,  cutting  pieces  of  corkboard  neatly  to 
fit  and  never  using  Portland  cement  mortar  to  fill  in  openings 
between  corkboards  or  pieces  of  corkboard. 

Give  the  cement  backing  ample  time  to  set,  at  least  48 
hours,  before  applying  a  finish  over  the  insulation. 

128. — Second  Layer  Corkboard,  to  First  Layer  on  Ceiling, 
in  Asphalt  Cement. — See  that  the  first  layer  of  corkboard  on 
the  ceiling  is  sc^idly  attached,  and  presents  a  reasonably 
smooth  and  level  surface*,  and  then  remove  all  dust,  dirt,  or 
other  foreign  material,  before  making  preparations  to  erect  a 
second  layer  of  corkboard  in  Asphalt  cement. 

Saw  sufficient  corkboards  lengthwise  down  the  center  so 
as  to  have  enough  half-width  pieces  to  make  one  row  along 
one  side  of  the  ceiling.  Cut  a  piece  6  inches  wide  and  27 
inches  long  with  which  to  start  setting  the  half-width  pieces 
in  proper  position  to  the  ceiling  area,  in  a  straight  line,  and 
against  the  edge  of  the  wall. 

Prepare  suitable  Asphalt  cement  in  reasonable  quantity, 
distribute  it  to  heated  pans,  add  the  proper  proportion  of 
cork  dust  and  mix;  dip  one  flat  side,  one  end  and  one  edge 
of  the  special  corkboard  pieces  in  the  molten  material,  lay  up 
the  first  row  to  the  surface  of  the  first  layer  of  insulation, 
slightly  press  into  place  and  additionally  secure  with  galvan- 
ized wire  nails  or  wood  skewers,  as  specified,  driven  ob- 
liquely, three  per  square  foot.  Keep  the  pieces  of  corkboard 
in  perfect  alignment,  so  that  the  joints  in  the  rows  to  follow 
may  fit  close  and  seal  tight. 

Then  start  with  a  full-width  and  9-inch  long  piece  of  cork- 
board and  set  the  second  row  of  full-size  corkboards  adjacent 
to  the  first  row,  thus  breaking  all  joints  in  the  second  layer, 
and  all  joints  in  the  second  layer  with  respect  to  all  joints 

*If  necessary,  cnt  off  any  protrudiug  corners  or  edges  of  corkboard  with  a  suit«ble 


DIRECTIONS  FOR  CORKBOARD  ERECTION  295 

in  the  first  layer.  As  each  corkboard  is  laid  up,  butt  and  seal 
it  tightly  at  all  points  of  contact  against  the  adjacent  boards, 
and  additionally  secure  to  the  first  layer  with  galvanized  wire 
nails  or  wood  skewers,  as  specified,  driven  obliquely,  three 
per  square  foot.  When  the  opposite  end  and  the  opposite  side 
of  the  ceiling  area  is  reached,  cut  pieces  of  corkboard  neatly 
to  fit  and  seal  with  the  wall  lines  of  the  room. 

Give  the  Asphalt  cement  ample  time  to  cool  and  set,  say 
12  hours,  before  applying  a  finish  over  the  insulation. 

129. — Double  Layer  Corkboard,  Self-supporting  T-iron 
Ceiling,  Portland  Cement  Mortar  Core. — Before  starting  the 
construction  of  this  self-supporting,  or  "false,"  ceiling,  see  that 
the  wall  insulation  rises  above  the  line  of  the  under  side  of 
the  finished  ceiling  to  be  constructed,  a  distance  equal  to  the 
thickness  of  the  under  layer  of  corkboard.  Cut  the  T-irons 
to  a  length  equal  to  the  width  of  the  room  plus  the  total  thick- 
ness of  the  two  walls,  set  and  space  the  T-irons  on  the  top 
edges  of  the  side  wall  insulation,  spanning  the  room,  parallel 
to  each  other  and  12  inches  between  vertical  sections  (not  12 
inches  from  center  to  center),  and  then  anchor  the  T-irons 
with  large  head  galvanized  wire  nails  driven  obliquely  into 
the  top  edges  of  the  wall  insulation. 

Place  one  layer  of  full-size  corkboards  between  the  ver- 
tical sections  of  the  T-irons  and  resting  on  the  flanges  or 
horizontal  sections  of  the  T-irons,  butting  the  ends  of  adjacent 
boards  tight.  Apply  a  1-inch  thick  Portland  cement  finish 
over  the  corkboard  and  the  T-irons,  mixed  one  part  Portland 
cement  to  two  parts  clean,  sharp  sand,  and  give  the  cement 
time  to  set,  at  least  48  hours,  before  applying  the  second  layer 
of  ceiling  insulation. 

Prepare  a  suitable  Portland  cement  mortar  in  reasonable 
quantity,  coat  one  side  of  each  corkboard  with  a  half-inch  of 
Portland  cement  mortar,  by  the  hopper  method,  lay  up  a  row 
to  the  under  side  of  the  first  layer,  in  a  straight  line,  against 
the  long  wall  of  the  room,  pressing  the  boards  firmly  into  place 
and  additionally  securing  with  galvanized  wire  nails,  driven 
obliquely,  three  per  square  foot.  Keep  the  corkboards  in  per- 
fect alignment,  so  that  the  joints  in  the  rows  to  follow  may  fit 
close  and  seal  tight. 


296 


CORK  INSULATION 


Break  all  joints  between  the  different  rows,  by  starting 
alternate  rows  w4th  half-length  boards,  and  break  all  joints  in 
the  second  layer  with  respect  to  all  joints  in  the  first  layer. 


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As  each  corkboard  is  laid  up,  butt  it  tightly  at  all  points  of 
contact  against  the  adjacent  boards,  and  additionally  secure 
to  the  first  layer  with  galvanized  wire  nails,  driven  obliquely, 


DIRECTIONS  FOR  CORKBOARD  ERECTION  297 

three  per  square  foot.  Join  the  second  layer  of  ceiling  insula- 
tion tightly  with  the  opposite  wall,  cutting  pieces  of  corkboard 
neatly  to  fit  and  never  using  Portland  cement  mortar  to  fill 
in  openings  between  corkboards  or  pieces  of  corkboard. 

Give  the  cement  backing  ample  time  to  set,  at  least  48 
hours,  before  applying  a  finish  to  the  under  surface  of  the 
insulation. 

130. — First  Layer  Corkboard,  over  Concrete  or  Wood 
Floor  or  Roof,  in  Asphalt  Cement. — See  that  the  concrete  or 
wood  surface  to  be  insulated  presents  a  smooth,  continuous 
solid  surface,  free  from  pits  or  open  cracks  and  loose  or  warped 
boards,  remove  all  dirt,  plaster,  paper,  loose  mortar,  or  other 
foreign  material,  or  arrange  to  have  these  several  items  taken 
care  of  by  those  responsible  for  such  preliminary  work,  before 
making  preparations  to  apply  corkboard  over  a  flat  surface  in 
Asphalt  cement. 

Prepare  suitable  Asphalt  cement  in  reasonable  quantity, 
transfer  it  to  the  point  of  erection  in  buckets,  flood  the  surface 
to  be  insulated  with  the  molten  material,  uniformly  over  a 
small  area  or  strip  at  a  time,  lay*  down  quickly  in  the  hot 
Asphalt  cement,  first  a  row  of  corkboards  against  the  edge  of 
the  wall,  in  a  straight  line,  and  closely  follow  with  a  second 
and  a  third  row  of  corkboards,  each  row  lagging  behind  the 
preceding  one,  in  the  laying,  by  the  length  of  one-half  board. 
Keep  the  corkboards  in  each  row  in  perfect  alignment,  so 
that  the  joints  in  the  rows  to  follow  may  fit  close  and  seal  tight. 

Break  all  joints  between  the  different  rows,  by  starting 
alternate  rows  with  half-length  boards,  and  see  that  all  joints 
are  butted  tight.  When  the  opposite  end  and  the  opposite 
side  of  the  floor  or  roof  area  is  reached,  cut  pieces  of  cork- 
board neatly  to  fit  and  seal  with  the  wall  lines. 

When  completed,  if  the  corkboard  was  laid  as  an  only 
layer  of  floor  insulation,  flood  the  top  surface  with  the  molten 
material  to  an  even  thickness  of  approximately  ^/^-inch,  and 
leave  in  readiness  for  the  concrete*  wearing  floor ;  if  the  cork- 
board was  laid  as  roof  insulation,  or  as  the  first  layer  of  a 
double  layer  floor  insulation,   leave   the  surface   of  the  cork- 

*I{  wood  floor  is  desired  over  single  layer  of  insulation,  instead  of  concrete,  then 
sleepers  must  be  embedded  in  the  single  layer  of  corkboard,  as  outlmed  in  Article  144. 


298 


CORK  INSULATION 


board  uncoated  and  in  readiness  for  the  roofing  contractor 
to  lay  the  roof,  or  in  readiness  for  the  insulation  contractor 
to  lay  down  the  second  layer  of  corkboard. 

131. — Second  Layer  Corkboard,  over  First  Layer  on  Floor 
or  Roof,  in  Asphalt  Cement.— See  that  the  first  layer  of  cork- 
board is  solidly  laid,  and  presents  a  reasonably  smooth  and 
level  surface*,  and  then  remove  all  dirt,  loose  mortar,  or  other 


FIG.    133.— APPLYING    FIRST   AND    SECOND    LAYERS    CORKBOARD    SIMUL- 
TANEOUSLY   OVER    CONCRETE    ROOF   IN    ASPHALT    CEMENT. 


foreign  material,  before  making  preparations  to  lay  a  second 
layer  of  corkboard  in  Asphalt  cement. 

Saw  sufficient  corkboards  lengthwise  down  the  center  so 
as  to  have  enough  half-width  pieces  to  make  one  row  along 
one  wall  of  the  area  to  be  insulated.  Cut  a  piece  6  inches 
wide  and  27  inches  long  with  which  to  start  laying  the  half- 


tool, 


If  necessary,  cut  off  any  protruding  corners  gr  edges  of  corkboard  with  a  -suitable 


DIRECTIONS  FOR  CORKBOARD  ERECTION  299 

width  pieces  in  proper  position  to  the  floor  or  roof  area,  in  a 
straight  line,  in  the  first  row  against  the  edge  of  the  wall. 

Prepare  suitable  Asphalt  cement  in  reasonable  quantity, 
transfer  it  to  the  point  of  erection  in  buckets,  flood  the  sur- 
face to  be  insulated  with  the  molten  material,  uniformly  over 
a  small  area  or  strip  at  a  time,  layf  down  quickly  in  the  hot 
Asphalt  cement  first  the  row  of  half-width  corkboards  against 
the  edge  of  the  wall,  follow  with  a  second  row  of  full-size 
corkboards  starting  off  with  a  full-width  and  9-inch  long  piece, 
and  then  wuth  a  third  row  of  full-size  corkboards  starting  off 
with  a  half-length  board,  each  row  lagging  behind  the  pre- 
ceding one,  in  the  laying,  by  the  length  of  one-half  board. 
In  this  way,  all  joints  in  the  second  layer  of  insulation  will 
be  broken  with  respect  to  all  joints  in  the  first  layer.  Keep 
the  corkboards  in  each  row  in  perfect  alignment,  so  that  the 
joints  in  the  rows  to  follow  may  fit  close  and  seal  tight.  When 
the  opposite  end  and  the  opposite  side  of  the  floor  or  roof 
area  is  reached,  cut  pieces  of  corkboard  neatly  to  fit  and  seal 
with  the  wall  lines. 

When  completed,  if  the  corkboard  was  laid  as  floor  insu- 
lation, flood  the  top  surface  with  the  molten  material  to  an 
even  thickness  of  approximately  ^-inch,  and  leave  in  readi- 
ness for  the  concrete*  w^earing  floor;  if  the  corkboard  w^as 
laid  as  roof  insulation,  leave  the  surface  of  the  corkboard 
uncoated  in  readiness  for  the  roofing  contractor  to  lay  the  roof. 

132. — Single  Layer  Corkboard,  Between  Partition  Studs 
with  Joints  Sealed  in  Asphalt  Cement. — Erect  2-inch  x  4-inch 
permanent  studs,  in  a  vertical  position,  36  inches  apart,  in  the 
line  of  the  partition,  so  that  the  2-inch  dimension  runs  with 
the  wall  thickness.  Place  permanent  studs,  with  a  lintel  be- 
tween them,  where  cold  storage  doors  are  to  be  set,  so  as  to 
form  an  opening  the  size  of  the  cold  storage  door  frame. 
Use  door  bucks  and  lintels  2  inches  in  thickness,  and  anchor 
securely  to  the  floor  and  ceiling  in  such  manner  that  they  may 
take  up  and  withstand  any  shock  from  the  operation  of  the 
cold  storage  door. 

Prepare  suitable  Asphalt  cement  in  reasonable  quantity,  on 
the  basis  of  one-quarter  pound  per  square  foot  of  partition 

*If  wood  floor  is  desired  over  double  layer  of  insulation,  instead  of  concrete,  then 
sleepers  must  be  embedded  in  the  second  layer  of  corkboard,  as  outlined  in  Article  144. 


300 


CORK  INSULATION 


area  (one  face  only),  distribute  it  to  heated  pans,  add  the 
proper  proportion  of  cork  dust  and  mix,  dip  both  ends  and 
one  edge  of  the  2-inch  thick  corkboards  in  the  molten  mate- 
rial, erect  the  first  row  on  the  floor  between  the  permanent 
studs,  on  a  level  line,  so  that  the  corkboards  in  the  entire  par- 
tition wall  are  kept  in  perfect  alignment,  and  all  vertical  joints 


FIG.     134.— DIAGRAMMATIC     ILLUSTRATION     OF     SINGLE     LAYER     CORK- 
BOARD  ERECTED  BETWEEN  PARTITION  STUDS  WITH  JOINTS  SEALED 

IN    ASPHALT    CEMENT. 


between  corkboards  and  studs,  and  all  transverse  joints  be- 
tween corkboards  in  all  rows,  are  made  to  fit  close  and  are 
sealed  tight.  Toe-nail  the  first  or  bottom  row  of  corkboards 
securely  to  the  floor,  if  the  floor  be  of  wood,  using  galvanized 
wire  nails,  and  drive  galvanized  wire  nails  through  the  corners 
of  each  corkboard  into  the  adjoining  studs. 

Join  and  seal  the  partition  insulation  tightly  with  the  ceil- 
ing, cutting  pieces  of  corkboard  neatly  to  fit,  additionally  toe- 


DIRECTIONS  FOR  CORKBOARD  ERECTION 


301 


nailing  if  the  ceiling  be  of  wood.  Cover  the  permanent  door 
bucks  and  lintels  with  corkboard,  as  specified,  nailed  in  place. 
Cover  the  exposed  edges  of  the  permanent  'partition  studs 
with  12-inch  wide  strips  of  galvanized  wire  square-mesh 
screen,  No.  18  gauge,  3  mesh  (J/^-inch),  securely  stapled  to 
the  studs  and  nailed  to  the  insulation  on  both  sides  of  the 
studs. 


fk;.   :,^^     i,kK(  rixo    mrst  i.a^kr   corkboard  of  self-supportii\g 

PARTITION  WITH  JOINTS  SEALED  IN  ASPHALT  CEMENT.— NOTE 
TEMPORARY  STUDS,  WHICH  ARE  REMOVED  WHEN  PARTITION  IS 
COMPLETED  TO  THE  POINT  OF  RECEIXING  FINISH  ON  SIDE  STUDS 
APPEAR. 

Give  the  Asphalt  cement  ample  time  to  cool  and  set,  say 
12  hours,  before  applying  a  finish  over  the  insulation. 

133. — First  Layer  Corkboard,  Self-supporting  Partition, 
Joints  Sealed  in  Asphalt  Cement. — Erect  temporary  studding 
on  18-inch  centers  on  a  line  with  one  side  of  the  proposed 
partition.  The  studs  must  he  erected  in  a  vertical  position 
and  in  perfect  alignment.  Erect  permanent  studs,  with  a 
lintel  between  them,  in  the  line  of  the  partition,  where  cold 


302  CORK  INSULATION  [ 

i 
storage  doors  are  to  be  set,  so  as  to  form  an  opening  the  size    \ 

of  the  cold  storage  door  frame.    Use  studs  and  lintels  of  the    i 

same    thickness    as    the    total    thickness    of    corkboard    to   be    ' 

erected,  and  anchor  the  permanent  studs  securely  to  the  floor    ' 

and  ceiling  in  such  manner  that  they  may  take  up  and  with-    i 

stand  any  shock  from  the  operation  of  the  cold  storage  door.    ■ 

Prepare  suitable  Asphalt  cement  in  reasonable  quantity,  ' 
on  the  basis  of  one-quarter  pound  per  square  foot  of  partition  ; 
area  (one  face  only),  distribute  it  to  heated  pans,  add  the 
proper  proportion  of  cork  dust  and  mix,  dip  but  one  end  and  i 
one  edge  of  the  corkboards  in  the  molten  material,  erect  the  i 
first  row  against  the  temporary  studs,  end  to  end  on  the  floor,  I 
on  a  level  line,  so  that  the  corkboards  in  the  entire  partition  , 
wall  are  kept  in  perfect  alignment  and  all  vertical  and  trans-  ; 
verse  joints  in  the  upper  rows  are  made  to  fit  close  and  are  - 
sealed  tight.  Toe-nail  the  first  or  bottom  row  of  corkboard  j 
securely  to  the  floor,  if  the  floor  be  of  wood,  using  galvanized 
wire  nails;  and  drive  long  galvanized  wire  nails  obliquely  ' 
through  the  corners  of  each  corkboard  into  the  abutting  cork-  1 
boards.  ' 

Cut  a  corkboard  half-length  and  with  it  start  setting  the    i 
second  row  on  top  of  the  first,  thus  l)reaking  vertical  joints,    i 
As  each  corkboard  is  set,  butt  and  seal  it  tightly  against  the    ', 
adjacent  boards  and  drive  long  galvanized  wire  nails  obliquely 
through  the  corners  of  each  corkboard  into  the  abutting  cork- 
boards, and  at  the  lower  corner  of  the  exposed  end  of  each 
board  drive  one  of  these  galvanized  wire  nails  obliquely  into 
the  corkboard  of  the  row  below. 

To  insure  the  corkboards  being  kept  in  perfect  alignment, 
as  the  rows  are  erected  edge  on  edge,  drive  small  headless 
nails  obliquely  through  the  upper  edge  of  each  row  of  cork- 
boards into  the  temporary  studs  at  occasional  points.  These 
nails  will  readily  pull  through  the  corkboards  when  the  tem- 
porary studs  are  later  removed. 

Join    and    seal    the    partition    insulation    tightly    with    the 
ceiling,   cutting  pieces   of  corkboard   neatly  to   fit,   and   addi- 
tionally toe-nailing  if  the  ceiling  be  of  wood.     Cover  the  per- 
manent studs  and  lintels,  on  the  side  away  from  the  tempo-    m 
rary  studding,  with  corkboard,  as  specified,  nailed  in  place.  m 

Before  removing  the  temporary  studs,  and  after  the  Asphalt 


I 


DIRECTIONS  FOR  CORKBOARD  ERECTION 


303 


cement  has  had  ample  time  to  cool  and  set  on  all  corkboard 
joints,  apply  the  finish  to  the  free  side  of  the  corkboard  par- 
tition, as  specified.  After  such  finish  has  had  ample  time  to 
set,  take  down  the  temporary  studs  and  apply  the  finish  to 
the  other  side  of  the  corkboard  partition,  or  leave  it  in  readi- 
ness to  receive  a  second  layer  of  corkboard  insulation. 

134. — Second   Layer   Corkboard,    Against   First   Layer   of 
Self-supporting   Partition,   in   Portland   Cement   Mortar. — See 


FIG.  136.— ERECTING  SECOND  LAYER  CORKliOAKD  AGAINST  FIRST  LAYER 
OF  SELF-SUPPORTING  PARTITION  IN  PORTLAND  CEMENT  MORTAR. 
—NOTE  ALSO  THE  METHOD  OF  INSULATING  COLUMNS  AND  CAPS 
AND  METHOD  OF  SETTING  DOOR  BUCKS  AND  LINTEL. 


that  the  first  layer  of  corkboard  of  the  self-supporting  partition 
is  solidly  erected,  and  presents  a  reasonably  smooth  and  level 


3(X  CORK  INSULATION 

surface*,  and  then  remove  all  dust,  dirt,  or  loose  mortar,  before 
making  preparations  to  erect  a  second  layer  of  corkboard  in 
Portland  cement  mortar. 

Now  see  that  the  floor  at  the  base  of  the  wall  is  free  from 
obstruction,  and  is  level ;  because  the  first  row  of  corkboards 
in  the  second  layer  must  be  applied  to  the  first  layer  at  the 
floor,  on  a  level  line,  so  that  the  corkboards  on  the  entire 
second  layer  are  kept  in  perfect  alignment  and  all  vertical 
and  transverse  joints  in  the  upper  rows  are  made  to  fit  close 
and  are  sealed  tight. 

Prepare  suitable  Portland  cement  mortar  in  reasonable 
quantity,  saw  sufficient  corkboards  lengthwise  down  the  center 
so  as  to  have  enough  half-width  pieces  to  make  one  row  along 
the  partition,  coat  the  half-width  corkboards  on  one  side  with 
a  half-inch  of  Portland  cement  mortar,  cut  a  piece  6  inches 
wide  and  27  inches  long  and  with  it  start  putting  the  half- 
width  pieces  of  corkboard  in  proper  position  against  the  first 
layer  of  insulation,  slightly  press  into  place  and  additionally 
secure  with  wood  skewers  driven  obliquely,  two  skewers  per 
square  foot. 

Then  start  "with  a  full-width  and  9-inch  long  piece  of  cork- 
board and  set  the  second  row  of  full-size  corkboards  on  top 
of  the  first  row,  thus  breaking  vertical  joints  in  the  second 
layer,  and  all  joints  in  the  second  layer  with  respect  to  all 
joints  in  the  first  layer.  As  each  corkboard  is  set,  butt  it 
tightly  at  all  points  of  contact  against  the  adjacent  boards 
and  additionally  secure  to  the  first  layer  with  wood  skewers 
driven  obliquely,  two  skewers  per  square  foot.  Join  the  wall 
insulation  tightly  with  the  ceiling,  cutting  pieces  of  corkboard 
neatly  to  fit  and  never  use  Portland  cement  mortar  to  fill  in 
openings  between  corkboards  or  pieces  of  corkboard. 

Give  the  cement  backing  ample  time  to  set,  say  48  hours, 
before  applying  a  finish   over  the  insulation. 

135. — Second  Layer  Corkboard,  Against  First  Layer  of 
Self-supporting  Partition,  in  Asphalt  Cement. — See  that  the 
first  layer  of  corkboard  of  the  self-supporting  partition  is  sol- 
idly erected,  and  presents  a  reasonably  smooth  and  level  sur- 

*If  necessary,  cut  oflE  any  protruding  corners  or  edges  of  corkboard  with  a  suitable 
tool. 


DIRECTIONS  FOR  CORKBOARD  ERECTION  305 

face,  and  then  remove  all  dust,  dirt,  or  loose  mortar,  before 
making  preparations  to  erect  a  second  layer  of  corkboard  in 
Asphalt  cement. 

Now  see  that  the  floor  at  the  base  of  the  wall  is  free  from 


FIG.     137.— ERECTING     DOUBLE     LAYER     CORKBOARD     SEI^F-SUPPORTING 

PARTITIONS  TO  FORM  CORRIDOR  WALLS  OF  UNUSUAL  HEIGHT.— 

NOTE   TEMPORARY   STUDS,   WHICH    ARE    LATER   REMOVED. 

obstruction,  and  is  level ;  because  the  first  row  of  corkboards 
in  the  second  layer  must  be  applied  to  the  first  layer  at  the 


506 


CORK  INSULATION 


floor,  on  a  level  line,  so  that  the  corkboards  on  the  entire 
second  layer  are  kept  in  perfect  alignment  and  all  vertical  and 
transverse  joints  in  the  upper  rows  are  made  to  fit  close  and 
are  sealed  tight. 

Prepare  suitable  Asphalt  cement  in  reasonable  quantity, 
distribute  it  to  heated  pans,  add  the  proper  proportion  of  cork 
dust  and  mix.  Saw^  sufficient  corkboards  lengthwise  down  the 
center  so  as  to  have  enough  half-width  pieces  to  make  one 
row   along  the   partition,   cut   a   piece   6  inches  wide   and  27 


FIG.  138.— ERECTING  SECOND  LAYER  CORKBOARD  To  FIRST  LAYER  IN 
PORTLAND  CEMENT  MORTAR  TO  WALLS,  CEILING  AND  BEAMS.— 
NOTE  SCAFFOLDING,  SHORING,  EXTENSION  CORD,  MORTAR  BOARD 
AND  OTHER  EQUIPMENT  REQUIRED. 


inches  long  and  with  it  start  putting  the  half-width  pieces  of 
corkboard  in  proper  position  against  the  first  layer  of  insula- 
tion, first  dipping  one  flat  side,  one  end  and  one  edge  of  each 
piece  in  the  molten  material,  slightly  pressing  into  place  and 
additionally  securing  with  wood  skewers  driven  obliquely, 
two  skewers  per  square  foot. 


DIRECTIONS  FOR  CORKBOARD  ERECTION  307 

Then  start  with  a  full-width  and  9-inch  long  piece  of  cork- 
board  and  set  the  second  row  of  full-size  corkboards  on  top 
of  the  first  row,  thus  breaking  vertical  joints  in  the  second 
layer,  and  all  joints  in  the  second  layer  with  respect  to  ail 
joints  in  the  first  layer.  As  each  corkboard  is  set,  butt  it 
tightly  at  all  points  of  contact  against  the  adjacent  boards  and 
additionally  secure  to  the  first  layer  with  wood  skewers 
driven  obliquely,  two  per  square  foot.  Join  and  seal  the  wall 
insulation  tightly  wMth  the  ceiling,  cutting  pieces  of  corkboard 
neatly  to  fit. 

Give  the  asphalt  cement  ample  time  to  cool  and  set,  say 
12  hours,  before  applying  a  finish  over  the  insulation. 

136. — Double  Layer  Corkboard,  Freezing  Tank  Bottom,  in 
Asphalt  Cement. — See  that  the  concrete  base  is  well  adapted 
to  the  ]nirpose  and  presents  a  reasonably  smooth  and  level 
surface,  remove  all  dirt,  loose  mortar,  or  other  foreign  mate- 
rial, or  arrange  to  have  these  several  items  taken  care  of  by 
those  responsible  for  such  preliminary  work,  before  making 
preparations  to  apply  corkboard  over  the  surface  of  the  freez- 
ing tank  foundation. 

Prepare  suitable  Asphalt  cement  in  reasonable  quantity, 
transfer  it  to  the  point  of  erection  in  buckets,  flood  the  surface 
to  be  insulated*  with  the  molten  material,  uniformly  over  a 
small  area  or  strip  at  a  time,  lay  down  cjuickly  in  the  hot 
Asphalt  cement,  first  a  row  of  corkboards  in  a  straight  line 
against  the  outer  edge  of  the  area  of  the  tank  bottom  insula- 
tion, closely  follow  with  a  second  and  a  third  row  of  cork- 
boards, each  row  lagging  behind  the  preceding  one,  in  the 
laying,  by  the  length  of  one-half  board.  Keep  the  cork- 
boards in  each  row  in  perfect  alignment,  so  that  the  joints  in 
the  rows  to  follow  may  fit  close  and  seal  tight. 

Break  all  joints  between  the  different  rows,  by  starting 
alternate  rows  with  half-length  boards,  and  see  that  all  joints 
are  butted  tight.  Carry  the  insulation  on  both  ends  and  both 
sides  to  the  outer  limits  of  the  end  and  side  insulation  of  the 
tank,  cutting  pieces  of  corkboard  as  required  to  finish  out  such 
dimensions. 


*The  dimen-ions  of  the  tank  bottom  area  to  be  insulated  shall  be  enough  wider  and 
longer  than  the  size  of  the  freezing  tank,  so  as  to  overlap  the  insulation  to  be  in- 
stalled  on  the  vertical  ends  and   sides  of  the  tank. 


308  CORK  INSULATION 

See  that  the  first  layer  of  corkboard  is  solidly  laid,  and 
presents  a  reasonably  smooth  and  level  surface.  Saw  suffi- 
cient corkboards  lengthwise  down  the  center  so  as  to  make 
one  row  along  the  one  side  of  the  insulated  area,  laying  the 
half-width  pieces  in  the  first  row  of  the  second  layer,  in  a 
straight  line,  starting  oflf  with  a  piece  6  inches  wide  and  27 
inches  long,  then  lay  a  second  row  of  full-size  corkboards, 
starting  off  with  a  full-width  and  9-inch  long  piece,  and  then 
lay  a   third  row  of  full-size  corkboards,   starting  off  with   a 


FIG.  139.— LAYING  SECOND  LAYER  CORKBOARD  ON  FLOOR  IN  ASPHALT 
CEMENT— TANK    BOTTOM    INSULATION   IS   APPLIED   IN    SAME   MANNER. 

half-length  board,  following  the  same  method  of  laying  as 
described  for  the  first  layer  of  insulation.  In  this  way,  all 
joints  in  the  second  layer  will  be  broken  and  made  tight,  and 
all  joints  in  the  second  layer  will  be  broken  with  respect  to 
all  joints  in  the  first  layer.  When  completed,  flood  the  top 
surface  with  the  molten  material  to  an  even  thickness  of 
approximately  ^-inch,  and  leave  in  readiness  for  the  tank 
to  be  set. 

137. — Regranulated  Cork  Fill,  Freezing  Tank  Sides  and 
Ends,  With  Retaining  Walls.— See  that  the  tank  has  been 
properly  set,  having  its  bottom  edges  the  proper  distance  in 
from  the  edges  of  the  insulation  underneath.  Erect  2-inch  x 
12-inch  studs  on  suitable  centers  (from  24  to  36  inches)  at 
right  angles  against  the  sides  and  ends  of  the  tank*,  anchoring 
carefully   by   cutting   slots  through   tank   bottom   insulation, 


*If  the  tank  is  to  be  set  in  a  corner,  so  that  masonry  walls  of  the  building  act  as 
two  retaining  walls,  such  walls  must  be  damp-proofed  before  the  tank  is  set  and  the 
loose  fill  insulation  is  placed. 


DIRECTIONS  FOR  CORKBOARD  ERECTION  309 

chiseling  slight  depressions  in  the  concrete  base,  dropping  the 
studs  into  these  slots  and  depressions  and  wedging  their  tops 
under  and  securing  them  with  suitable  metal  clips  to  the  flange 
at  the  top  of  the  tank.  Sheath  the  studs  with  double  layer  7,i- 
inch  T.  &  G.  boards,  having  two  layers  of  waterproof  paper 
between,  and  securely  nail  to  the  studs. 

Fill  the  space  between  the  retaining  walls  and  the  sides 
and  ends  of  the  tank  with  regranulated  cork  (by-product 
from  the  manufacture  of  pure  corkboard),  and  tamp  well  until 
there  is  sufficient  in  place  to  avoid  future  settling.  Then 
install  a  curbing,  as  and  if  specified,  over  the  regranulated 
cork  fill. 

138. — Single  Layer  Corkboard  and  Regranulated  Cork  Fill, 
Freezing  Tank  Sides  and  Ends. — See  that  the  tank  has  been 
properly  set,  having  its  bottom  edges  the  proper  distance  in 
from  the  edges  of  the  insulation  underneath.  Erect  4-inch  x 
4-inch  studs  on  18-inch  centers  at  right  angles  against  the 
sides  and  ends  of  the  tank*,  anchoring  carefully  by  cutting 
slots  through  tank  bottom  insulation,  chiseling  slight  depres- 
sions in  the  concrete  base,  dropping  the  studs  into  these  slots 
and  depressions  and  wedging  their  tops  under  and  securing 
them  with  suitable  metal  clips  to  the  flange  at  the  top  of  the 
tank. 

Prepare  suitable  Asphalt  cement  in  reasonable  quantity, 
on  the  basis  of  one-quarter  pound  per  square  foot  of  cork- 
board area  (one  face  only),  distribute  it  to  heated  pans,  add 
the  proper  proportion  of  cork  dust  and  mix,  dip  both  ends 
and  one  edge  of  the  corkboards  in  the  molten  material,  erect 
the  first  row  against  the  studs,  end  to  end,  on  a  level  line,  so 
that  the  corkboards  are  kept  in  perfect  alignment,  and  all 
•  vertical  and  transverse  joints  in  the  upper  rows  are  made  to 
fit  close  and  are  sealed  tight.  Break  all  joints  between  the 
different  rows,  by  starting  alternate  rows  with  half-length 
boards,  and  as  the  rows  are  erected  edge  on  edge,  securely 
fasten  the  corkboards  to  the  studs  by  nailing  with  galvanized 
wire  nails,  two  per  square  foot.     Carry  the  insulation  to  the 

*If  the  tank  is  to  be  set  in  a  corner,  so  that  masonry  walls  of  the  building  act 
as  two  retaining  walls  for  regranulated  cork  fill  on  one  side  and  one  end  of  the  tank, 
such  walls  must  be  damp-proofed  before  the  tank  is  set  and  the  loose  fill  insulation  is 
placed. 


310 


CORK  INSULATION 


line  of  the  flange   at  the   top  of  the   tank,  cutting  pieces  of 
corkboard  neatly  to  fit. 

Fill  the  space  between  the  insulation  and  the  sides  and 
ends  of  the  tank  with  regranulated  cork  (by-product  from 
the  manufacture  of  pure  corkboard),  and  tamp  well  until  there 
is  sufficient  in  place  to  avoid  future  settling.  Then  install  a 
curbing,  as  and  if  specified,  over  the  side  and  end  insulation. 


:.g  -4"~t"3TUD5  3&"C.TOC: 

e"co;^»<.  BCARD  — 

A3PH^LT 

E'COR^  BOM2D  NMLCO 
WITH  WCDD  3CEWER3 
CEMENT  PL^OTEe — » 

ruooR     LINE  -y 


2  LAvVEC:5  5" 

COQ.^  EO^RD    LMD  IN 

HOT    ASPHALT     


PLAN 


^ 


^^ 


FIG.    140.— PLAN  AND  SECTION   OF   FREEZING  TANK  INSULATION. 

139. — Double  Layer  Corkboard,  Freezing  Tank  Sides  and 
Ends. — See  that  the  tank  has  been  properly  set,  having  its  bot- 
tom edges  the  proper  distance  in  from  the  edges  of  the  insula- 
tion underneath.  Erect  studs  (2-inch  by  a  dimension  equival- 
ent to  the  thickness  of  the  first  layer  of  corkboard  specified  to 
be  applied  to  tank  sides  and  ends)  at  right  angles  against  the 
sides  and  ends  of  the  tank*,  and  36  inches  apart,  anchoring 
carefully  by  cutting  slots  through  tank  bottom  insulation, 
chiseling  slight  depressions  in  the  concrete  base,  dropping 
the  studs  into  these  slots  and  depressions  and  wedging  their 


*If  the  tank  is  to  be  set  in  a  corner,  so  that  masonry  walls  of  the  building  act 
as  two  retaining  walls  for  regranulated  cork  fill  on  one  side  and  one  end  of  the  tank, 
such  walls  must  be  damp-proofed  before  the  tank  is  set  and  the  loose  fill  insulation  is 
placed. 


DIRECTIONS  FOR  CORKBOARD  ERECTION  311 

tops  under  and  securing  them  with  suitable  metal  clips  to  the 
flange  at  the  top  of  the  tank. 

Prepare  suitable  Asphalt  cement  in  reasonable  quantity,  on 
the  basis  of  one  pound  per  square  foot  of  corkboard  area  (one 
face  only),  distribute  it  to  heated  pans,,  add  the  proper  pro- 
portion of  cork  dust  and  mix,  dip  one  flat  side,  both  ends  and 
one  edge  of  the  corkboards  in  the  molten  material,  erect  the 
first  row  between  the  studs  and  against  the  tank,  on  a  level 
line,  so  that  the  corkboards  are  kept  in  perfect  alignment,  and 
all  vertical  joints  between  corkboards  and  studs,  and  all  trans- 
verse joints  between  corkboards  in  the  upper  rows  to  follow, 
are  made  to  fit  close  and  are  sealed  tight.  Drive  galvanized 
wire  nails  through  the  corners  of  each  corkboard  and  into  the 
adjacent  studs.  Carry  the  insulation  to  the  line  of  the  flange 
at  the  top  of  the  tank,  cutting  pieces  of  corkboard  neatly  to  fit. 

Saw  sufficient  corkboards  lengthwise  dowm  the  center  so 
as  to  have  enough  half-width  pieces  to  make  one  row  in  a 
second  layer  around  the  tank,  cut  a  piece  6  inches  wide  and  18 
inches  long  and  with  it  start  putting  the  half-width  pieces  of 
corkboard  in  proper  position  against  the  first  layer  of  insu- 
lation, first  dipping  one  flat  side,  one  end  and  one  edge  of  each 
piece  in  the  molten  material,  slightly  pressing  into  place  and 
additionally  securing  with  wood  skewers  driven  obliquely, 
two  skewers  per  square  foot. 

Then  start  with  a  full-width  and  9-inch  long  piece  of  cork- 
board and  set  the  second  row  of  full-size  corkboards  on  top 
of  the  first  row,  thus  breaking  vertical  joints  in  the  second 
layer,  and  all  joints  in  the  second  layer  with  respect  to  all 
joints  in  the  first  layer.  As  each  corkboard  is  set,  butt  it 
tightly  at  all  points  of  contact  against  the  adjacent  boards 
and  additionally  secure  to  the  first  layer  with  wood  skewers 
driven  obliquely,  two  skewers  per  square  foot.  Carry  the  in- 
sulation to  the  line  of  the  flange  at  the  top  of  the  tank,  cutting 
pieces  of  corkboard  neatly  to  fit.  Then  install  a  curbing,  as 
and  if  specified,  over  the  side  and  end  insulation. 

140. — Portland  Cement  Plaster. — See  that  the  exposed  sur- 
face of  the  corkboard  to  receive  the  Portland  cement  plaster 
presents  a  reasonably  smooth  and  le\cl  sr.rfacc*  and  that  all 


*If  necessary,  cut  off  any  protruding  corners  or  edges  of  corkboard  with  a  suitable 
tool. 


312 


CORK  INSULATION 


corkboards  are  butted  tight,  score  the  surface  of  the  cork- 
board  (if  preferred)  by  roughening  slightly  with  a  pronged 
tool,  such  as  a  few  wire  nails  driven  through  a  piece  of  wood, 
so  as  possibly  to  increase  the  bond  for  the  cement  plaster,  and 
then  remove  all  dust,  dirt,  or  other  foreign  material,  or  arrange 
to  have  these  several  items  taken  care  of  by  those  responsible 
for  such  preliminary  work,  before  making  preparations  to  apply 
a  Portland  cement  plaster  finish  to  the  exposed  surface  of 
corkboard  insulation. 

Prepare   suitable    Portland    cement    mortar   in    reasonable 


FIG.     141.— CORKBOARD    INSULATED     COLD     STORAGE     ROOM     FINISHED 
WITH   PORTLAND  CEMENT   PLASTER   SCORED  IN  4-FT.   SQUARES. 

quantity,  mixed  one  part  Portland  cement  to  two  parts  clean, 
sharp  sand,  with  no  lime  added.  Be  sure  the  sand  is  clean 
and  free  from  loam,  and  that  it  is  sharp. 

Apply  the  first  coat  of  plaster  approximately  ^-inch  in 
thickness,  rough  scratch,  and  leave  until  thoroughly  dried  out. 
Then  apply  the  second  coat  to  the  first,  also  approximately 
^^-inch  in  thickness,  and  trowel  to  a  hard,  smooth  finish. 
Score  the  surface  of  the  finished  plaster  in  squares,  as  specified, 


DIRECTIONS  FOR  CORKBOARD  ERECTION  313 

using  suitable  scoring  tool  only,  so  as  to  confine  any  checking 
or  crackingf  of  the  plaster  to  such  score  marks. 

141. — Factory  Ironed-on  Mastic  Finish. — See  that  the  ex- 
posed surface  of  the  factory  ironed-on  mastic  finish  is  reason- 
ably level,  and  that  all  joints  between  the  coated  corkboards 
are  butted  tight. 

Prepare  suitable  mastic  filler  for  the  V  jomts  of  the  coated 
corkboards,  by  following  the  directions  furnished  by  the 
manufacturer,  which  directions  frequently,  but  not  always, 
consist  in  heating  the  mastic  filler  until  plastic  by  immersing 
in  hot  water  and  working  up  a  small  quantity  at  a  time  in  the 
hand  like  putty*. 

Fill  the  joints  between  the  mastic  coated  corkboards  with 
the  prepared  mastic  material  in  such  practical  manner  as  will 
eliminate  all  voids.  Then  follow  with  an  electric  iron,  or 
heated  pointing  trowel,  applying  sufficient  heat  to  melt  the 
edges  of  the  coating  on  the  corkboards  so  that  it  will  flow 
into  and  amalgamate  with  the  mastic  filler  in  the  joints,  mak- 
ing a  continuous  and  permanent  seal. 

142, — Emulsified  Asphalt  Plastic. — See  that  the  exposed 
surface  of  the  corkboard  to  receive  the  emulsified  asphalt 
plastic  presents  a  reasonably  smooth  and  level  surface§,  and 
then  remove  all  dust,  dirt,  or  other  foreign  material,  or  arrange 
to  have  these  several  items  taken  care  of  by  those  responsible 
for  such  preliminary  work,  before  making  preparations  to 
apply  emulsified  asphalt  plastic  finish  to  the  exposed  surface 
of  corkboard  insulation. 

Shake  or  roll  the  barrel  or  cylinder  in  which  the  emulsified 
asphalt  plastic  is  supplied,  before  opening;  and  if  water  is 
found  standing  on  the  surface,  work  it  into  the  mass  before 
using.  After  a  container  is  opened,  it  should  be  kept  covered, 
to  prevent  the  drying  out  of  the  material  and  coalescence  of 
the  asphalt  particles.   The  emulsified  asphalt  plastic,  if  a  ready 


tCracks  fre(|uently  develoii  in  plaster  at  the  lop  corners  of  door  franies.  which 
can  usuallv  be  prevented  bv  setting  and  stapling  pieces  of  galvanized  wire  square- 
mesh  screen  (No.  18  gauge,'  3  mesh)  to  the  corkboard  over  such  comers  and  at  an 
angle  of  45  degrees  before  the  plaster  is  applied.  ,        ,  ,.  r 

*It  is  essential  that  the  material  furnished  bv  the  manufacturer  for  the  sealing  of 
the  joints  be   prepared  and  used  as  directed  by   the  manufacturer. 

§If  necessary,  cut  off  any  protruding  corners  or  edges  of  corkboard  with  a  suitable 
tool. 


314 


CORK  INSULATION 


mixed  product*,  should  be  applied  exactly  as  received,  without 
adding  sand  or  any  other  material  whatever.  If,  by  reason  of 
evaporation,  the  product  is  too  heavy  to  work  easily  under  a 
trowel,  add  as  little  as  possible  of  clean  water,  working  it  well 
through  the  mass. 

Apply  the  first  coat  of  emulsified  asphalt  plastic  approxi- 
mately 3/32-inch  in  thickness,  keeping  the  trowel  wet,  and 
working  the  material  well  into  the  surface  voids  of  the  cork- 
board.  Then  apply  the  second  coat  to  the  first,  after  the  first 
coat  has  set  up,  approximately  1/32-inch  in  thickness,  and 
trowel  as  smooth  as  the  material  will  permit.  After  the  sec- 
ond coat  has  taken  its  initial  set,  sprinkle  with  water  and 
trowel  again,  to  obtain  a  smooth,  hard  surface. 

Do  not  score  the  surface  of  the  emulsified  asphalt  plastic 
finish,  unless  specified. 

143. — Concrete  Wearing  Floors. — See  that  the  exposed  sur- 
face of  the  corkboard  has  been  flooded  to  a  thickness  of 
approximately  ^-inch  with  hot  odorless  asphalt,  so  that  the 
entire  surface  of  the  insulation  is  thoroughly  protected. 


H 


JN    HOT    AAPHfi^LT 

E"   COU-K,     bOA.t2,D  — 

HOT        Ac5PMAvL.T 

b"cjONcc.LTL  rLOOC  auNroccLD 

WITH    WICLL  NLTTlNCj.  I"  OLMLNT  TINI^H 


FIG.  142.— DIAGRAMMATIC  ILLUSTRATION  OF  CONCRETE  WEARING 
FLOOR  (REINFORCED)  OVER  DOUBLE  LAYER  COUKBOARD  ON 
COOLER  FLOOR. 


Prepare  suitable  concrete  in  reasonable  quantity,  mixed 
one  part  Portland  cement  to  two  and  one-half  parts  clean, 
sharp  sand,  and  five  parts  clean  gravel  or  crushed  stone. 
Cover  the  corkboard  to  a  depth  of  3  inches  with  the  concrete, 
tamp  until  the  water  comes  to  the  surface,  and  let  stand  until 


*If  the  emulsified  asphalt  plastic  material  is  not  a  ready  mixed  product,  then  pre- 
pare the   material  for  use   only  as  directed  by  the  manufacturer. 


DIRECTIONS  FOR  CORKBOARD  ERECTION 


315 


thoroughly   dry,   about   48   hours,   before   applying   the   finish 
coat. 

Prepare  suitable  Portland  cement  mortar  in  reasonable 
quantity,  mixed  one  part  Portland  cement  to  one  part  clean, 
sharp  sand,  and  then  apply  a  top  coat,  of  minimum  depth  of 
1  inch,  over  the  rough  concrete  base,  slope  to  drain  as  specified, 
and  trowel  to  a  smooth,  hard  surface. 

144. — Wood  Floors  Secured  to  Sleepers  Embedded  in  In- 
sulation.— Embed  wood  sleepers,  2  inches  wide  and  of  suitable 
thickness,  in  the  single  or  the  second  layer  of  corkboard,  as 
the  case  may  be,  by  putting  the  sleepers  in  place,  parallel  to 


ftcONcaLTE-   PLOOR. 

' a'COB-K-  BO^CX) 

A^PHAL-T 
S'COTiK.  BOA.C.D 
S\a:-  NA.1UIMO  i)TRJP.' 


FIG.      143.— DIAGRAMMATIC     ILLUSTRATION      OF     WOOD     FLOOR      OVEK 
DOUBLE    LAYER    CORKBOARD   APPLIED    OVER    CONCRETE    SLAB. 

each  other,  on  38-inch  centers,  and  lay  down  a  layer  of  cork- 
board  in  suitable  hot  Asphalt  cement  between  the  sleepers 
with  all  joints  carefully  butted  and  sealed  tight.  The  top  sur- 
face of  the  corkboards  and  the  sleepers  shall  then  be  flooded 
with  the  same  compound  to  a  uniform  thickness  of  approxi- 
mately ^-inch. 

Lay  a  finished  wood  floor  of  thoroughly  dry  and  seasoned 
J^-inch  lumber,  as  specified,  with  approximately  1/32-inch 
between  the  boards,  to  eliminate  as  much  as  possible  the 
tendency  of  the  floor  to  expand  and  warp,  secret  nail  securely 
to  the  sleepers  embedded  in  the  corkboard  underneath,  and 
leave  the  surface  of  the  floor  perfectly  smooth  and  even. 

145. — Galvanized  Metal  Over  Corkboard. — Embed  wood 
sleepers,  2  inches  wide  and  of  suitable  thickness,  in  the  single 
or  the  second  layer  of  corkboard,  as  the  case  may  be,  on  the 


316  CORK  INSULATION 

floors  and  baffles  of  bunkers,  on  such  centers  as  to  permit 
lapping  the  galvanized  metal  joints  1  inch,  over  such  sleepers, 
and  anchoring  thereto  by  securely  nailing. 

Apply  the  metal  of  specified  gauge  and  suitable  width, 
extending  it  over  all  edges  of  the  bunker  at  least  2  inches 
and  lapping  all  joints  1  inch  over  sleepers,  and  then  anchor 
at  all  points  by  securely  nailing. 

Carefully  and  permanently  solder  all  joints  and  nail  heads 
in  the  finished  work,  and  leave  the  surface  of  the  metal  per- 
fectly smooth  and  even. 


CORK  INSULATION 

Part   IV — The    Insulation    of   Household    Refriger- 
ators, Ice  Cream  Cabinets  and  Soda  Fountains. 

CHAPTER  XV. 

HISTORY  OF  REFRIGERATION  EMPLOYED  TO 
PRESERVE  FOODSTUFFS. 

146. — Early  Uses  of  Refrigeration. — Preservation  of  food 
through  the  use  of  snow  and  ice  undoubtedly  was  practised 
several  centuries  before  the  Christian  era  in  those  climates 
and  regions  where  the  preservation  of  the  snow  and  ice  in 
turn  during  the  short  summer  season  was  accomplished  by 
Nature  through  natural  storage  in  caves.  During  the  long 
winters,  large  quantities  of  snow  and  ice  accumulated  in  shel- 
tered spots  and  never  entirely  melted  away  during  the  warmer 
season  of  the  year  that  followed.  Such  crevices  and  caves 
afforded  natural  cold  storages,  for  fish  and  meat,  and  there  is 
every  reason  to  believe  that  they  were  so  employed.  Later, 
perhaps  as  early  as  1000  B.  C,  snow  was  artificially  stored 
in  caves,  and  used  for  cooling  and  preserving.  At  any  rate, 
Simonides,  the  early  Greek  poet,  who  lived  about  500  B.  C, 
when  made  angry  by  observing  other  guests  at  the  board 
treated  to  snow  poured  into  their  liquor,  while  he  sipped 
warm  wine,  enscribed  the  ode  that  concludes  "for  no  one  will 
commend  the  man  who  gives  hot  water  to  a  friend."  It  is 
also  known  that  Alexander  the  Great,  King  of  Macedon  (336- 
323  B.  C.)  had  trenches  dug  and  filled  with  snow  to  cool 
hundreds  of  kegs  of  wine  to  be  given  to  his  soldiers  on  the 
eve  of  battle,  and  Nero,  Roman  Emperor  (37-68  A.  D.),  had 
his  wines  cooled  by  snow  brought  down  from  the  mountains 
by  slaves.  It  may  therefore  be  assumed  that  by  the  first 
century  the  luxury  of  drinking  cooled  liquors  was  enjoyed 
rather  generally  by  kings  and  emperors  and  their  friends. 

317 


318 


CORK  INSULATION 


History  also  shows  that  the  ancient  Egyptians,  on  the 
other  hand,  knew  the  secret  of  cooling  liquids  by  evaporation, 
which  method  of  cooling  is  practised  today  by  the  natives  of 
India,  as  well  as  by  the  desert  traveller,  and  quite  probably 
by  many  others.  The  ancient  Egyptians  placed  shallow  trays, 
made  of  porous  material  and  filled  with  water,  on  beds  of 
straw,  and  left  them  exposed  to  the  night  winds.  Through 
the  resultant  evaporation,  the  water  became  chilled  sometimes 


•ARTIST'S    CONCEPTION    OF    ANCIENT    EGYPTIANS    PREPARING 
WATER   FOR   CHILLING   BY   EVAPORATION. 


to  the  extent  of  a  thin  film  of  ice  on  the  surface.  Today,  in 
the  upper  provinces  of  India,  water  is  made  to  freeze  during 
cold,  clear  nights  by  leaving  it  overnight  in  porous  vessels,  or 
chilled  in  containers  that  are  wrapped  in  moistened  cloth.  In 
the  first  instance,  the  water  freezes  by  virtue  of  the  cold 
produced  by  its  own  evaporation ;  and  in  the  second  instance, 
the  water  is  rapidly  cooled  by  the  drying  of  the  moistened 
wrapper.  In  Bengal  the  natives  resort  to  a  still  more  elabo- 
rate plan.  Pits  are  dug  about  two  feet  deep  and  filled  three- 
quarters  full  with  dry  straw,  on  which  are  set  flat,  porous 
pans  containing  water.  Exposed  overnight  to  a  cool,  dry, 
gentle  wind  from  the  northwest,  the  water  evaporates  at  the 
expense  of  its  own  heat  with  sufificient  rapidity  to  overbalance 


HISTORY  OF  REFRIGERATION  319 

the  slow  influx  of  heat  from  above  through  the  cooled  dense 
air,  or  from  below  through  the  badly  conducting  straw,  and 
the  water  freezes.  The  desert  traveller  carries  water  in  a 
porous  canvas  water  bag  so  as  to  have,  through  slow  evapo- 
ration, a  supply  of  drinking  water  sufficiently  palatable  to 
dampen  his  parched  lips  and  cool  his  throat. 

The  use  of  saltpetre  mixed  with  snow  for  cooling  and 
freezing  liquids  was  known  and  employed  at  a  remote  period 
in  India.  In  1607  Tancrelus  mentioned  the  use  of  this  mix- 
ture to  freeze  water,  and  in  1626  Santono  mentioned  the  use 
of  common  salt  and  snow  to  freeze  wine.  At  about  that  same 
time,  in  Italy,  iced  fruits  put  in  an  appearance  at  table,  and 
during  the  17th  century  a  method  of  congealing  cream  was 
discovered. 

Lord  Francis  Bacon,  English  scientist,  philosopher  and 
statesman  (1561-1626),  appreciated  what  a  useful  thing  it 
would  be  if  man  could  have  the  same  command  of  cold  as  of 
heat,  and  undertook  experiments  into  its  possibilities  that 
terminated  in  his  death.     Among  his  notes  there  is  this: 

Heat  and  cold  are  Nature's  two  hands  whereby  she  chiefly 
worketh,  and  heat  we  have  in  readiness  in  respect  of  the  fire, 
but  for  cold  we  must  stay  till  it  cometh  or  seek  it  in  deep 
caves  or  high  mountains,  and  when  all  is  done  we  cannot 
obtain  it  in  any  great  degree,  for  furnaces  of  fire  are  far 
hotter  than  a  summer's  sun,  but  vaults  and  hills  are  not  much 
colder  than  a   winter's   frost. 

History  is  filled  with  interesting  references  to  the  early 
use  of  snow  and  natural  ice,  especially  by  the  French,  Span- 
iards and  Italians,  devotees  of  better  living.  In  England,  the 
sale  of  natural  ice  from  the  wagons  of  fishmongers  was  an 
early  practice  that  continues  to  this  day.  In  the  United  States 
•a  cargo  of  natural  ice  was  sent  from  New  York  to  New 
Orleans  in  1799,  the  first  delivery  of  natural  ice  to  an  American 
home  was  made  in  1802,  and  Frederick  Tudor  exported  natural 
ice  from  the  United  States  to  the  West  Indies  in  1805  to  help 
stay  the  ravages  of  yellow  fever. 

147. — The  Formation,  Harvesting  and  Storing  of  Natural 
Ice. — The  formation  of  ice  is  a  very  common  phenomenon  of 
Nature,  but  the  exact  process  followed  in  converting  water 


320 


CORK  INSULATION 


into  natural  ice  is  not  generally  understood  by  those  who  make 
use  of  the  resultant  product. 

That  water  freezes  at  32°  F.  at  a  pressure  of  one  atmos- 
phere is  generally  understood.  When  the  air  above  a  body 
of  water  is  chilled  to  a  temperature  below  that  of  the  water, 
heat  is  transferred  from  the  water  to  the  air,  the  top  layer  of 
water  is  chilled,  it  becomes  denser  than  the  water  underneath, 
drops  to  the  bottom,  and  is  replaced  by  other  water  rising  to 


FIG.  145.— LOADING  A  CARGO  OF  NATURAL  ICE  AT  NEW  YORK  FOR  SHIP- 
MENT TO  NEW  ORLEANS   IN   1799. 

be  similarly  chilled.  But  this  chilling  process  continues  only 
until  the  entire  body  of  the  water  is  cooled  to  39.1°  F.,  which 
is  the  point  of  the  greatest  density  of  water,  the  temperature 
at  which  water  is  heaviest,  but  a  temperature  not  yet  low 
enough  to  cause  the  water  to  freeze.  Further  cooling  of  the 
water  on  the  pond,  lake  or  stream  will  no  longer  cause  the 
top  layer  of  water  to  drop,  by  convection,  and  the  chilling 
efifect  is  thereafter  concentrated  on  the  surface  of  the  water 
instead  of  being  applied  generally  to  the  entire  body  of  the 
water.  When  the  temperature  of  the  top  layer  of  water 
reaches  32°  F.,  ice  forms,  and  increases  in  thickness  as  the 
water  in  contact  underneath  is  chilled,  by  conduction,  to  the 
freezing  point. 


HISTORY  OF  REFRIGERATION  321 

Each  particle  of  water,  in  freezing,  sets  free  the  air  that 
was  contained  in  that  water,  and  the  tiny  bubbles  of  air  cling 
to  the  newly  frozen  ice  crystals,  unless  dislodged.  If  these 
bubbles  are  not  dislodged,  by  agitation,  then  other  ice  cr3^stals 
forming  adjacent  to  the  first  ones  entrap  the  clinging  air  bub- 
bles to  form  opaque,  or  "milky,"  ice.  Opaque  ice  is  usually 
found  on  ponds  where  the  water  is  not  in  motion,  or  on  slug- 
gish streams ;  while  clear,  hard  ice  is  frozen  on  bodies  of  water 
that  are  in  motion  sufficiently  to  free  the  newly  formed  ice 
crystals  of  all  clinging  air  particles. 


FIG.   146.— HARVESTING  XAIVRAL  ICE   FROM  A  NORTHERN   LAKE 

The  development  of  the  scientific  harvesting  of  natural  ice 
is  an  interesting  chapter  in  itself,  and  second  in  importance 
only  to  the  development  of  the  use  of  natural  ice  as  a  refrig- 
erant for  the  preservation  of  foodstufifs.  It  must  be  sufficient 
to  mention  here  that  during  the  latter  half  of  the  19th  cen- 
tury enormous  quantities  of  natural  ice  came  to  be  harvested 
and  stored  in  huge  ice  houses,  ice  houses  of  moderate  size 
and  little  ice  houses,  located  almost  in  every  community  in 
the  United  States  where  the  temperature  dropped  low  enough 
at  some  time  during  the  winter  to  freeze  ice  on  the  ponds,  lakes 
and  streams.  The  very  large  ice  houses  were  scientifically 
•constructed  and  equipped,  and  were  insulated  between  wood 
walls  with  shavings  and  sawdust  well  tamped.  The  smaller 
ice  houses,  especially  those  in  the  rural  communities,  were 
often  crudely  built,  simply  of  wood  slabs  nailed  to  one  side 
of  the  timber  framing.  In  the  well-built  and  insulated  ice 
houses,  straw  was  frequently  used  between  layers  or  tiers 
of  ice  blocks,  and  sometimes  sawdust  was  thus  employed, 
to  insulate  the  several  layers  from  each  other  and  to  keep 


322 


CORK  INSULATION 


them  from  freezing  together;  but  the  insulation  between  the 
double  walls  of  the  structure  was  relied  upon  for  the  reason- 
able preservation  of  the  ice  during  the  warmer  months,  while 
the  house  was  being  emptied  of  its  valual3le  contents.  The 
ice  was  stored  in  the  smaller  uninsulated  structures  in  such 
fashion  that  a  space  of  approximately  two  feet  was  left  all 
around  the  house  between  the  walls  and  the  pile  of  ice  blocks. 
This  space  was  filled  with  sawdust  as  the  tiers  of  ice  were 


FIG.   147.— TVl'ICAL  ICE  STOR.\GE  HOUSES  FOR  N.\TURAL  TCE.  SITUATED 
AT   SOURCE  OF   SUPPLY. 


laid,  and  sawdust  was  sometimes  placed  between  layers  to  a 
thickness  of  several  inches.  Over  the  top  layer,  sawdust  was 
piled  to  a  depth  of  several  feet;  and  louvre-windows  at  dif- 
ferent levels  in  either  end  of  the  house  served  to  ventilate 
the  space  over  the  ice  and  directly  under  the  uninsulated  roof, 
to  prevent  superheating  of  the  air  in  that  space  on  summer 
days  with  consequent  excessive  meltage  of  the  ice  in  the  top 
layers. 

The  business  of  harvesting,  storing  and  dispensing  large 
quantities  of  natural  ice  was  built  on  the  constantly  growing 
demand  for  the  use  of  such  ice  by  brewers,  packers  and  large 
dealers  in  food  products,  the  trade  gradually  extending  to  the 


HISTORY  OF  REFRIGERATION 


323 


FIG.    148.— GIFFORD-WOOD    ICE    STORAGE    HOUSE    EQUIPMENT. 


324  CORK  INSULATION 

smaller  establishments,  then  to  the  retail  stores,  and  finally 
to  countless  homes,  especially  in  the  congested,  large  city 
areas.  This  trade  had  extended  gradually  each  year  and  had 
grown  to  enormous  proportions,  but  its  real  size  and  scope 
was  not  fully  appreciated,  and  the  necessity  for  ice  was  not 
generally  understood,  until  the  summer  of  189D,  when  the 
greatest  shortage  in  the  crop  of  natural  ice  that  has  ever 
occurred  in  the  United  States  resulted  from  the  exceptionally 
mild  preceding  winter  season.  This  unusual  shortage  gave 
mechanical  refrigeration  an  impetus  such  as  it  never  had  be- 
fore, and  marks  the  real  beginnings  of  the  use  of  ice  as  a 
necessity  of  life. 

148. — The  Development  of  the  Ice  Machine. — The  earliest 
machine  to  produce  ice  by  purely  mechanical  means  was  of 
the  "vacuum"  type,  built  by  Dr.  William  Cullen  in  1755.  In 
this  class  of  "liquid"  machine,  since  the  refrigerating  liquid 
is  itself  rejected,  the  only  agent  cheap  enough  to  be  employed 
is  water.  The  boiling  point  of  water  varies  with  pressure; 
and  at  a  pressure  of  one  atmosphere  (14.7  pounds  per  square 
inch)  the  boiling  point  is  212°  F.,  whereas  at  a  pressure  of 
0.085-pound  per  square  inch  it  is  32°  F.,  and  at  lower  pres- 
sures there  is  still  further  fall  in  temperature.  Water  at  ordi- 
nary temperature  is  placed  in  an  air-tight,  insulated  vessel, 
and  when  the  pressure  is  reduced  by  means  of  a  vacuum 
pump  it  begins  to  boil,  the  heat  necessary  for  evaporation  be- 
ing taken  from  the  water  itself.  The  pressure  being  still 
further  reduced,  the  temperature  is  gradually  lowered  until 
the  freezing  point  is  reached  and  ice  formed,  when  about  one- 
sixth  of  the  original  volume  has  been  evaporated.  Dr.  Cullen 
is  said  to  have  produced  the  vacuum  by  means  of  a  pump 
alone. 

In  1810,  Sir  John  Leslie  combined  with  the  air  pump  a 
vessel  containing  strong  sulphuric  acid  for  absorbing  the  vapor 
from  the  air,  and  is  said  to  have  produced  several  pounds  of 
ice  in  a  single  operation.  Val lance  of  France,  in  1824,  pro- 
duced another  machine  for  the  same  purpose. 

Several  suggestions  had  been  made  with  regard  to  the 
production  of  ice  by  the  evaporation  of  a  more  volatile  liquid 
than  water,  but  the  first  machine  actually  constructed  and 


HISTORY  OF  REFRIGERATION 


325 


operated  on  that  princii^le  was  built  in  1834  from  the  designs 
of  Jacob  Perkins,  an  American  living  abroad,  who  that  year 
took  out  patents  in  England  on  an  ether  machine.  This  ma- 
chine, though  never  actually  used  commercially,  is  the  parent 
of  all  modern  compression  machines.  James  Harrison,  of  Gee- 
long,  Victoria,  later  worked  out  the  Perkins  principle  in  a 
more  complete  and  practical  manner  and  in  1861  had  his  ma- 
chine adopted  successfully  in  England  for  the  cooling  of  oil 
to  extract  paraffin. 


FIG.    149.— EARLY   TYPE    REFRIGERATING    MACHINE. 


Meanwhile,  Michael  Faraday,  English  chemist  and  physi- 
cist (1791-1867),  succeeded  in  condensing  ammonia  gas  to  a 
liquid  by  applying  pressure  and  then  cooling  it.  When  the 
pressure  was  removed,  the  liquid  boiled  off  rapidly  as  a  gas, 
absorbing  heat,  as  any  liquid  will  do  when  it  turns  into  a  gas. 
Faraday's  discovery,  made  in  about  1826,  proved  of  the  great- 
est importance,  both  practically  and  theoretically. 

Professor  A.  C.  Twining,  of  New  Haven,  Connecticut,  and 
Dr.  John  Gorrie,  of  Appalachicola,  Florida,  also  contributed 
|o  the  successful  development  of  the  ice  machine.  Dr.  Gorrie 
taking  out  the  first  American  patent  in  1850  for  a  practical 
process  of  manufacturing  ice. 

In  1858,  E.  C.  Carre  adopted  the  same  principle  as  Sir 
John  Leslie,  but  used  a  solution  of  ammonia  and  water  in 
his  vacuum  machine  to  make  ice.  The  first  one  of  these 
Carre  machines  to  reach  the  United  States  ran  the  blockade 
of  New  Orleans  in  1863.  Dr.  A.  Kirk  invented  an  air  ma- 
chine, in  1862,  which  was  fully  described  by  him  in  a  paper 


326  CORK  INSULATION 

on  the  "Mechanical  Production  of  Cold,"  being  simply  a  re- 
versed Sterling  air  engine,  the  air  working  in  a  closed  cycle 
instead  of  being  actually  discharged  into  the  room  to  be  cooled, 
as  is  the  usual  practice  with  compression  machines.  It  is 
said  that  Kirk's  machine  was  used  commercially  with  success 
on  a  fairly  large  scale,  chiefly  for  ice  making,  producing  about 
4  pounds  of  ice  per  pound  of  coal. 

In  1870,  the  subject  of  refrigeration  was  investigated  by 
Professor  Carl  Linde,  of  Munich,  Germany,  who  was  the  first 
to  consider  the  question  from  a  thermodynamic  point  of  view. 
He  dealt  with  the  coefficient  of  performance  as  a  common  basis 
of  comparison  for  all  machines,  and  showed  that  the  compres- 
sion vapor  machine  more  closely  reached  the  theoretical  maxi- 
mum than  any  other.  Linde  also  examined  the  physical  prop- 
erties of  various  liquids,  and,  after  making  trials  with  methylic 
ether  in  1872,  built  his  first  ammonia  compression  machine  in 
1873.  In  the  next  two  years,  these  machines  were  introduced 
into  the  United  States  by  Professor  Linde,  and  David  Boyle 
of  the  United  States.  From  then  until  the  ice  shortage  of 
the  summer  of  1890,  many  new  forms  of  apparatus  were  pro- 
duced and  certain  important  improvements  were  made,  follow- 
ing which  the  rapid  development  and  practical  utilization  of 
the  art  of  ice  making  and  refrigeration  grew  by  leaps  and 
bounds,  until  today  ice  and  refrigeration  may  be  had  at  any 
time  and  anywhere  that  power  can  be  obtained. 

149. — Early  Methods  of  Utilizing  Ice  as  a  Refrigerant. — 

Just  as  snow  was  used  in  ancient  times  to  cool  the  cup  that 
cheered,  so  harvested  natural  ice  was  probably  first  employed 
in  later  times  to  cool  wines  and  preserve  beer.  Deep  cellars 
were  dug,  walled  with  heavy  masonry,  and  divided  longitud- 
inally by  arched  stone  ceilings  into  top  cellars  and  sub- 
cellars.  The  goods  to  be  preserved  were  placed  in  the  lower 
or  sub-cellars  and  the  ice  was  filled  into  the  top  cellars  just 
above,  an  ingenious  and  effective  arrangement  that  permitted 
the  storing  of  sufficient  quantities  of  natural  ice,  as  harvested, 
to  carry  the  sub-cellars  through  the  warm  summer  months  at 
temperatures  cool  enough  for  many  purposes.  Such  cellars 
were    probably    the    first    man-made    cold    storage    houses   or 


HISTORY  OF  REFRIGERATION 


327 


refrigerating  plants,  the  suggestion  having  no  doubt  come 
down  from  the  early  days  of  the  utilization  of  snow  and  ice 
found  in  the  summer  months  in  deep  rocky  crevices  and 
natural  caves  of  the  mountains. 

These  underground  masonry  caverns  were  not  insulated, 
except  naturally  by  the  earth,  but  their  heavy  masonry  walls, 
once  cooled,  acted  as  enormous  reservoirs  of  cold.  Many  of 
these  storage  cellars  were  constructed  in  Europe,  especially 


FIG.    ISO.— SAWDUST   INSULATED  NATURAL  ICE  HOUSE. 


in  Germany,  and  many  more  of  them  were  built  later  in  the 
1  United  States,  particularly  in  connection  with  breweries,  in 
*the  early  days  when  a  simpler  and  cheaper  method  of  guaran- 
1  teeing   summer    refrigeration    was   unknown.       However,    as 

time  passed,  ice  storages  and  cooling  rooms  were  arranged  in 

single  tier  cellars,  by  locating  the  cold  room  within  the  ice 
I  storage,  so  to  speak,  and  having  less  height,  so  that  the  ice 

could  be  piled,  as  harvested,  around  and  over  the  cold  room. 
'  Another  type  of  cold  storage  and  ice  storage  combined  was 
[  constructed  by  digging  a  cellar  into  the  side  hill  and  building 


328  CORK  INSULATION 

the  four  walls  of  thick  masonry,  as  the  food  storage  compart- 
ment, with  a  double  layer  plank  ceiling  laid  over  heavy  joists, 
and  then  building  a  double-thick  plank-walled  ice  house  over 
such  structure.  Then  boards  and  air  spaces'  took  the  place 
of  the  double  layer  plank  walls  above  ground,  and  holes  were 
cut  in  the  floor  to  let  the  cold  through.  It  was  only  a  step, 
of  course,  from  the  cutting  of  holes  in  the  floor  alongside  of 
the  ice  to  permit  the  cold  air  to  drop  into  the  room  below, 
to  a  practical  bunker  arrangement  and  an  efficient  air  circu- 
lation, which  was  the  forerunner  of  the  present  indispensible 
overhead  bunker.  The  sawdust  insulated  natural  ice  house 
next  came  into  being  along  the  shores  of  northern  rivers  and 
lakes,  the  first  large  ice  house  in  the  United  States  having 
been  built  on  the  shores  of  the  Hudson  river  in  1805 ;  and 
from  then  on  the  development  of  the  use  of  natural  ice  as  a 
refrigerating  medium  was  rapidly  extended.  Farmers,  for 
instance,  put  up  ice  in  cheaply  constructed  ice  houses,  sur- 
rounded the  ice  stores  with  sawdust  as  insulation,  kept  fresh 
meats  in  sacks  buried  among  the  blocks  of  ice,  used  the  ice 
to  cool  milk,  to  keep  butter,  and  otherwise  to  serve  useful 
purposes  incident  to  farm  life.  Simultaneously,  in  the  cities, 
insulated  coolers  were  being  constructed  in  certain  retail 
establishments,  and  in  the  better  homes  portable  ice  chests 
were  installed,  natural  ice  delivery  service  having  been  estab- 
lished in  the  larger  cities,  which  functioned  as  far  into  the 
summer  as  the  supply  of  natural  ice  lasted. 

It  may  now  appear  to  be  a  curious  fact,  but  a  fact  it  re- 
mains nevertheless,  that  the  breweries  had  equally  as  much 
to  do  with  the  extension  of  the  use  of  natural  ice,  and  later 
of  manufactured  ice,  as  had  any  other  single  agency.  For, 
first  of  all,  the  brewing  of  beer  was  a  profitable  business,  and 
the  industry  attracted  capital.  Some  of  the  finest  plants  in 
the  world  were  breweries.  They  could  aflford  to  harvest  and 
store  ice  in  their  cellars,  to  be  among  the  very  first  to  install 
ice  machines  for  the  manufacture  of  ice,  to  re-equip  their 
plants  for  mechanical  cooling,  and  to  experiment  with  dif- 
ferent kinds  of  insulation.  As  a  means  of  widening  the  market 
for  beer,  especially  after  the  advent  of  manufactured  ice, 
portable  coolers  in  large  quantities  were  built  by  the  breweries 


HISTORY  OF  REFRIGERATION  329 

and  loaned  out  to  inns,  hotels,  saloons  and  a  variety  of  estab- 
lishments, ice  being  delivered  daily  in  generous  quantities, 
often  at  no  extra  cost  whatever,  with  which  to  cool  the  boxes 
and  their  contents.  Perishable  foods  soon  found  their  way 
into  those  refrigerators,  where  it  was  kept  cool  with  the  beer, 
at  the  expense  of  the  brewery.  The  conveniences  and  bene- 
fits accruing,  however,  from  the  consistent  use  of  ice-cooled, 
insulated  boxes  created  a  demand  on  the  part  of  others,  in 
other  lines  of  business,  for  a  like  refrigeration  service  for 
the  handling  of  perishable  foodstuffs,  and  the  breweries  were 
the  first,  in  many  instances,  to  provide  the  public  with  such 
service  and  at  a  very   nominal   cost  indeed. 

150. — Early  Methods  of  Insulating  Cold  Stores. — Hollow 
walls,  or  air  chambers  or  spaces,  were  the  very  first  artificial 
barriers  used  in  cold  stores  to  retard  the  influx  of  heat,  some 
of  the  first  installations  being  made  on  ships,  to  permit  of 
the  exporting  and  importing  of  perishables,  particularly  fresh 
meats,  from  one  country  to  another.  Later  it  became  the 
practice,  especially  in  cold  storage  structures,  to  lay  up  double 
walls  and  fill  the  space  between  with  a  light-weight,  loose 
material.  Powdered  charcoal,  sawdust,  diatomaceous  earth 
and  similar  materials  were  thus  employed,  and  except  for  the 
gradual  loss  of  the  insulation  from  settling  and  sifting  out,  the 
loss  of  storage  space  due  to  the  bulkiness  of  the  insulation,  the 
fire  hazard,  and  so  forth,  such  insulated  cold  stores  proved 
satisfactory  in  service,  using  ice  as  the  refrigerant  and  operat- 
ing at  temperatures  sufficiently  high  to  obviate  the  condensa- 
tion of  enough  moisture  within  the  insulation  to  seriously 
interfere  with  its  heat  retarding  qualities. 

But  with  the  real  advent  of  mechanical  refrigeration  in  ice 
and  cold  storage  plants,  following  the  summer  of  1890,  and 
the  gradual  use  of  temperatures  lower  than  were  ever  ob- 
tained with  ice,  or  with  salt  and  ice  mixtures,  serious  diffi- 
culties began  to  be  experienced  with  insulated  structures.  If 
the  insulation  was  l:)()ards  and  air  spaces,  or  double  wall 
frame  construction  with  loose  fill  insulation,  the  wood  fre- 
quently became  soaked  with  water,  and  rotted  away,  or  the 
loose  fill  insulation  became  water-logged  and  of  no  further 
value    as    an    insulator,    meanwhile    throwing    a    heavy    extra 


330  CORK  INSULATION 

load  on  the  refrigerating  apparatus  and  equipment,  and  of 
course  increasing  the  cost  of  operation  excessively.  At  such 
points  in  the  insulation  where  the  wood  remained  perfectly 
dry,  there  was  great  danger  of  dry-rot,  consequent  weakening 
of  supporting  members,  and  danger  to  the  safety  of  the 
structure.  It  was  not  at  all  uncommon  to  have  the  entire 
over-head  bunker  structure  drop  to  the  floor  because  of  dry- 
rot  or  wet-rot  of  the  supporting  timbers  at  the  points  where 
the  members  pie'rced  the  thick  walls  of  insulation  to  gain  sup- 
port in  the  outer  walls  of  the  building.  If  the  construction 
consisted  of  double  walls  of  masonry,  with  inside  surfaces 
pitched,  and  the  intervening  space  filled  with  a  loose  insulat- 
ing material,  the  loose  fill  material  settled  and  packed  down 
and  frequently  became  thoroughly  water-logged  and  of  no 
further  value  whatever  as  an  insulator. 

Every  possible  precaution  was  taken  to  wateruroof  the 
walls  between  which  the  loose  fill  insulation  was  placed,  such 
as  coating  them  with  expensi^'e  pure  resin  pitch,  imported 
from  afar,  probably  on  the  theory  that  water  got  into  the 
insulation  by  penetrating  such  walls.  However,  water  con- 
tinued to  be  condensed  out  of  the  air  in  the  countless  voids 
between  particles  of  the  insulation,  from  the  fact  of  the  cold 
storage  rooms  operating  at  temperatures  low  enough  to  throw 
the*  dew  point  within  the  insulation,  fresh  air  carrying  more 
water  was  automatically  drawn  in,  the  insulation  sucked  up 
the  precipitated  water  by  capillarity  and  soon  became  com- 
pletely water-logged,  as  formerly. 

Meanwhile,  in  Europe,  cork,  possessing  no  capillarity  but 
high  in  insulating  value  because  of  its  sealed  air  cell  struc- 
ture, was  being  formed  into  slabs  by  gluing  the  cork  particles 
together  with  a  hot  mixture  of  certain  clays  and  asphalt,  and 
these  slabs  were  applied  to  the  walls  of  cold  storage  rooms 
as  insulation,  and  the  results  were  heralded  as  being  very 
satisfactory.  The  Armstrong  Cork  Company  subsequently 
acquired  the  United  States  patent  rights  for  this  "impreg- 
nated" type  of  corkboard  insulation,  and  constructed  a  factory 
at  Beaver  Falls,  Pennsylvania,  for  its  production.  Large 
quantities  of  this  impregnated  corkboard  were  purchased  and 
installed,  especially  by  the  breweries ;  but  it  was  later  dis- 


I 


HISTORY  OF  REFRIGERATION  331 

covered  that  such  "composition"  corkboard  was  inferior  in 
structural  strength  and  insulating  quality  to  pure  corkboard 
manufactured  under  the  patents  of  John  T.  Smith,  and  with 
the  purchase  of  the  Nonpariel  Cork  Manufacturing  Company 
and  the  Smith  patents,  by  the  Armstrong  Cork  Company,  com- 
position corkboard  virtually  disappeared  from  the  market.  In 
competition  with  pure  corkboard,  however,  there  was  offered 
very  early  a  great  variety  of  insulating  boards  or  slabs,  made 
from  fibrous  materials  of  one  sort  or  another  and  possessing 
marked  affinity  for  water;  but  experience  in  service  with  all 
such  substitutes  for  pure  corkboard  clearly  and  conclusively 
demonstrated  wherein  they  were  unsuited  for  cold  storage 
temperatures,  and  they  have  virtually  disappeared  from  the 
market  as  cold  storasre  insulating  materials. 


CHAPTER  XVI. 

DEVELOPMENT  OF  THE  CORKBOARD  INSULATED 
HOUSEHOLD  REFRIGERATOR. 

15L — Early  Forms  of  Household  Coolers. — Probably  the 
first  household  "cooler"  was  a  crude  box  anchored  in  a  nearby 
stream,  in  which  in  turn  several  tall  earthen  jars  or  pieces 
of  crockery  were  placed,  the  ends  of  the  box  provided  with 
slatted  openings  to  permit  the  fresh  water  to  pass  through, 


FIG.    151.— THE   FIRST   METHOD   OF   KEEPING   FOOD   COOL— A    BOX   IN  A 

NEARBY    STREAM    SERVED    THE   PURPOSE    OF    THE 

MODERN   REFRIGERATOR. 

and  the  top  of  the  box  covered  with  a  strap-hinged  lid.  If 
a  spring  of  water  was  available,  the  box  was  of  course  an- 
chored just  below  the  overflow  and  probably  in  a  slight  ex- 
cavation made  to  accommodate  it.  In  either  case,  perishable 
foods,  such  as  milk,  butter,  eggs  and  meat,  were  placed  within 
the  jars  or  crocks,  to  be  cooled  and  preserved  as  best  as 
possible. 

The  objection  to  this  simple  type  of  household  cooler  was 

332 


CORKBOARD  INSULATED  REFRIGERATOR 


233 


that  the  mid-day  sun  often  beat  down  upon  the  low,  flat  lid 
of  the  box  with  telling  effect  on  the  perishable  foodstuffs  just 
underneath,  and  at  night  the  lid  was  sometimes  disturbed 
and  the  food  stolen  by  prowling  marauders  of  the  field  and 
forest.  So  here,  as  elsewhere,  necessity  being  the  mother  of 
invention,  the  next  step  in  the  development  of  the  present 
household  refrigerator  was  the  construction  of  a  rude  shelter 
over  the  box  to  protect  the  food  from  the  elements  and  from 
unwelcome  guests.  This  shelter  was  made  of  logs,  as  a  min- 
iature log  cabin,  and  was  usually  spoken  of  as  the  "milk 
house,"  or  the  ''spring  house." 


'^mM 


a^}^^ 


-THE    SPRING   HOUSI-:     A    RUDE    SHELTER   BUILT    OVER   SPRl-NG 
OR   STREAM  TO   PROTECT  THE   FOOD   STORED. 


Long  before  cellars  were  excavated  under  dwellings,  some 
provision  had  to  be  made  for  the  storing  of  fruits  and,  more 
particularly,  vegetables  in  a  uniformly  cool  atmosphere  suffi- 
ciently dry  to  preserve  the  stores  as  far  into  the  next  season 
as  possible.     Natural  caves  were  occasionally  available,  but 

I  more  often  artificial  caves  were  dug  out  of  the  side  of  a  hill, 
lined  with  timbers  and  equipped  with  shelves,  bins  and  a 
strong  door.     Again,  where  a  hillside  was  not  conveniently 

'  near,  a  low,  log  room  was  constructed,   similarly  equipped, 

I  and  completely  surrounded  and  covered  with  earth  thrown  up 
in  the  form  of  a  mound.  The  mound  was  then  tamped  and 
covered  with  thick  sod,  which  made  a  suitable  storage  con- 

i  veniently  nearby  and  which  was  commonly  spoken  of  as  the 


334 


CORK  INSULATION 


"root  house,"  the  name  borrowed  from  still  earlier  times  when 
similar  provision  was  made  for  the  storing  of  roots  for  medi- 
cine.   When  cellars  were  first  excavated  under  dwellings,  they 


FIG.    153.— THE    "ROOT    HOUSE,^'    COVERED   WITH    HEAVY    SOD— A    COOL 
THE   YEAR   'ROUND  VEGETABLE   STORAGE. 

were  installed  as  a  substitute  for  the  outside  provision  cave  or 
root  house,  and  the  only  entrance  was  through  an  outside  cel- 
lar  door   so   as   to   avoid   direct   communication    between   the 


jfjt--^^''- ^_  ~'^_z — '=^\ 


FIG.     154.— ENTRANCE     TO     CELLAR— A     MORE     CONVENIENT     STORAGJi 
THAN  THE   "ROOT  HOUSE." 

heated  dwelling  above  and  the  cool  cavern  underneath.  These 
original  cellars  were  provision  storages  only  and  as  such  were 
little  more  than  pits  dug  in  the  ground. 


CORKBOARD  INSULATED  REFRIGERATOR 


335 


It  has  been  seen  how,  in  ancient  times,  trenches  were  dug 
and  filled  with  snow  to  cool  kegs  of  wine.  At  a  later  time, 
pits  were  dug,  filled  with  ice  and  roofed  over,  which  was 
probably  the  earliest  form  of  ice  storage  or  ice  house.  About 
the  middle  of  the  16th  century  the  rich  in  America  harvested 
and  stored  ice  in  private  ice  houses  built  of  logs  and  padded 
inside  between  the  logs  and  the  pile  of  ice  with  straw  packed 
tight,  and  later  with  sawdust.  The  blocks  of  ice  were  then 
used  in  a  heavy,  wooden  chest,  about  three  feet  wide  by  three 
feet  high  and  possibly  ten  or  twelve  feet  long,  resting  on  the 
floor,  usually  in  an  out-building  adjacent  to  the  kitchen,  in 
which  chest  earthen  containers  were  used  in  very  much  the 


FIG.  155.— FOREFATHER  OF  THE  MODERN  HOUSEHOLD  REFRIGERATOR 
—A  HEAVY  CHEST  CONTAINING  RECEPTACLES  FOR  FOOD  SUR- 
ROUNDED ]}Y  NATURAL  ICE  AND  WATER. 

same  way  as  they  were  in  the  earlier  crude  box  anchored 
!  in  the   stream   or   spring.      This   heavy,    water-tight,   wooden 

chest,  filled  with  ice  and  with  vessels  for  liquids  and  pro- 
ii visions  to  be  cooled  and  preserved,  having  as  a  drain  for  the 

water  of  meltage  merely  a  hole  in  the  end  of  the  chest  about 

half  way  up,  and  equipped  with  a  heavy,  hinged  lid,  was  the 
:  predecessor  of  the  household  ice-box  and  the  crude  forefather 

of  the  modern  household  refrigerator. 

152. — The  Household  Ice-box. — It  has  been  seen  that  hol- 
low walls,  or  air  spaces,  were  the  very  first  artificial  barriers 
'  used  in  cold  stores  to  retard  the  influx  of  heat,  which  method 
of  insulating  cold  temperatures  from  the  higher  temperatures 


336 


CORK  INSULATION 


of  the  surrounding  atmosphere  followed  upon  the  use  of  thick  ; 
masonry  walls  underground  and  of  walls  of  heavy  timbers  ' 
or  planks  in  structures  above  ground.  Following  the  same  i 
development,  and  true  to  tradition,*  the  ice  chest  in  time  ' 
became  an  ice-box,  smaller  in  length,  made  of  oak,  chestnut  ' 
or  other  hard  wood,  with  hollow  walls  lined  inside  with  sheet  [ 
zinc,  standing  upon  raised  feet  formed  from  prolongations 
of  the  side  posts,  a  hole  in  the  bottom  for  the  water  to  drain  '• 


FIG.    156.— SLIDING-TOP   HOUSEHOLD   ICE   CHEST. 


away,  with  perhaps  a  shallow  pan  underneath  to  catch  the 
drip.  The  very  first  of  these  ice-boxes  had  wood  pieces  laid 
in  the  bottom  to  keep  the  ice  and  food  from  contacting  with 
the  metal  lining,  but  there  was  no  provision  for  the  separa- 
tion of  the  food  from  the  ice.  The  lid,  usually  of  double  layer 
boards  with  no  air  space  between,  was  at  first  hinged,  and; 
later,  in  some  instances,  built  in  two  sections  and  made  to 
slide.  As  time  passed,  these  convenient  household  ice-boxes 
were  provided  with  a  vertical  division  across  the  box  at  the 


*The  box,  whatever  its  shape  or  purpose  or  the  materials  of  which  it  is  fashioned, 
is  the  direct  descendent  of  the  chest,  one  of  the  most  ancient  articles  of  domestic 
furnishings. 


CORKBOARD  INSULATED  REFRIGERATOR  337 

center  to  separate  the  food  from  the  ice,  but  it  was  at  that 
time  in  no  sense  a  baffle  for  the  promotion  of  air  circulation, 
the  idea  not  then  having  been  adapted  to  such  purpose. 

In  due  course,  it  became  the  practice  in  cold  stores  to  con- 
struct double  walls  and  fill  the  intervening  space  with  flaked 
charcoal,  silicate  cotton,  small  pumice,  sawdust,  and  similar 
loose  or   granular  materials;  and   the   principle  of  the   over- 


FIG.  IS/.— LIFT-LID   HOUSEHOLD  ICE  BOX. 


head  bunker  was  at  about  the  same  time  being  fast  developed 
to  a  point  of  efficiency  that  opened  up  new  avenues  of  use- 
;  fulness  for  cold  stores  employing  ice,  or  salt  and  ice  mix- 
itures,  as  the  refrigerant.  This  influence  was  quickly  reflected 
in  the  large  beer  and  meat  coolers  of  retail  establishments  and 
in  turn  in  the  household  ice-box,  flaked  charcoal  becoming  the 
preferred  type  of  loose  fill  insulation  between  ice-box  walls, 
followed  later  by  silicate  cotton,  or  mineral  wool.  Then  for 
the  first  time  the  household  ice-box  was  elevated,  so  to  speak. 


338 


CORK  INSULATION 


to  a  new  position ;  its  length  was  somewhat  decreased  in  favor 
of  a  much  greater  height,  and  the  division  between  the  ice  and 
the  food  changed  from  a  vertical  one  to  a  horizontal  one.  In 
a  word,  the  household  ice-box  became  a  household  "refrig- 
erator," of  the  kind  now  known  as  a  lid  tyi)e  top-icer,  b\  virtue  i 


FIG.    158.— LID    TYPE    TOP-ICER    HOUSEHOLD    REFRIGERATOR. 

of  the  location  of  the  ice  on  an  overhead  support  of  such 
design  as  to  utilize  the  fact  of  the  greater  weight  of  cold  than 
of  warm  air  to  cause  a  natural  circulation  to  be  set  up  through- 
out the  refrigerator.  Then  came  the  top-icer  with  a  side  ice- 
chamber  door;  and,  later,  the  side-icer  completed  the  inter- 
esting evolution  of  the  form  our  modern  household  refrigerator 
finally  came  to  take. 

Except  for  the  gradual  loss  of  the  insulation  from  settling 
and  sifting  out,  those  early  household  refrigerators  proved 
much  r^ore  satisfactory  in  service,  using  ice  as  the  refrigerant, 
than  did  the  cold  storage  rooms  in  plants  cooled  by  mechan- 


CORKBOARD  INSULATED  REFRIGERATOR 


339 


ical  means  and  insulated  in  exactly  the  same  manner.  Of 
course  the  rooms  cooled  by  mechanical  means  could  be,  and 
were,  held  at  lower  temperatures  than  were  the  household 
refrigerators  chilled  wdth  ice ;  and  this  fact  was  responsible  for 
the   different   degrees   of  success  experienced   with   the   same 


FIG.    159.— SIDE-DOOR   TOP-ICEK   HOUSEHOLD   REFRIGERATOR. 

•type  and  kind  of  insulation  under  those  different  conditions 
of  service;  for  it  will  be  recalled  that  with  the  gradual  use 
in  cold  stores  of  temperatures  lower  by  mechanical  means 
than  were  possible  with  ice,  serious  difficulties  began  to  be 
experienced   with   insulated   structures   from    condensation    of 

I'  water  within  the  insulation. 

153. — The   Era  of  Multiple  Insulation   in   Household   Re- 
frigerators.— Pliny,   writing  in   the   first  century,   said:     "The 


340  CORK  INSULATION 

natives  who  inhabit  the  west  of  Europe  have  a  liquid  with 
which  they  intoxicate  themselves,  made  from  corn  and  water. 
..The  people  in  Spain  in  particular  brew  this  liquid  so  well 
that  it  will  keep  good  a  long  time.  So  exquisite  is  the  cun- 
ning of  mankind  in  gratifying  their  vicious  appetites  that  they 
have  thus  invented  a  method  to  make  water  itself  produce 
intoxication."  It  has  been  seen  how  that  same  "exquisite 
cunning"  of  which  Pliny  wrote  also  provided  means  of  mak- 
ing that  ceria  more  palatable  and  soothing  by  cooling  with 
snow,  and  later  with  ice ;  how  the  physicist  working  in  the 
laboratory  formulated  certain  laws  which  apply  to  the  con- 
densation of  gases;  how  the  engineer,  in  his  workshop,  utilized 
these  fundamental  principles  to  develop  machines  to  make  ice 
on  a  hot  summer's  day ;  and  it  only  remained  for  the  prac- 
tical business  man  of  the  20th  centur}^  to  so  organize  the  ice 
industry  that  ice  is  no  longer  a  luxury,  to  be  obtained  only  by 
the  wealthy,  but  is  today  within  the  reach  of  almost  every- 
one. Sixteen  million  tons  of  natural  ice  are  harvested  and 
forty-two  million  tons  are  manufactured  each  year  in  the 
United  States  alone.  And  of  this  total  ice  production  of  fifty- 
eight  million  tons  (1923),  American  households  used  the  enor- 
mous total  of  twenty-five  million  tons. 

So  from  practically  nothing  at  the  beginning  of  the  19th 
century,  the  ice  industry  of  the  United  States  has  becon  e 
ninth  in  the  list  of  great  commercial  activities,  with  a  nioac- 
tary  involvement  of  over  one  billion  dollars,  which  mav  be 
accounted  for  by  the  increased  cost  of  foods,  a  better  knov,  !- 
edge  of  the  value  of  very  fresh  foods  in  the  diet,  a  more 
thorough  understanding  of  the  danger  of  stale  or  decomposed 
foods,  and  the  means  on  the  part  of  countless  numbers  of 
people  not  only  to  purchase  fresh  foods  the  year  'round  but 
also  to  provide  facilities  in  the  home  for  the  care  of  such 
perishables. 

The  many  industries  that  use  refrigeration  in  their  routine 
business  have  been  benefited  by  careful  scientific  research 
begun  many  years  ago ;  and  only  by  correctly  utilizing  the 
findings  of  engineers,  chemists,  physicists  and  bacteriologists 
have  they  been  able  to  reach  their  present  high  efficiency.  But 
similar  studies  applicable  to  the  problems  of  the  home  were 
never  undertaken  in   similar  concerted  fashion  by  either  the 


CORKBOARD  INSULATED  REFRIGERATOR  341 

ice  manufacturers  or  the  refrigerator  manufacturers,  and  even 
those  principles  worked  out  and  established  for  the  benefit  and 
guidance  of  the  ice  and  refrigerating  and  allied  industries, 
and  which  are  directly  applicable  to  the  household,  often  have 
been  overlooked,  ignored  or  misapplied. 

For  instance,  careful  scientific  research  established  the  fact 
that  the  flow  of  heat  through  a  given  insulating  material  was 
retarded  by  an  external  or  surface  resistance  as  well  as  by 
an  internal  resistance,  but  that  its  surface  resistance  virtually 
disappeared  if  the  surfaces  of  the  material  were  no  longer 
in  contact  with  the  surrounding  atmosphere,  as  elaborated  in 
the  section  of  this  book  on  "The  Study  of  Heat."  But  this 
scientific  fact  was  either  misunderstood,  or  its  true  significance 
ignored,  because  many  manufacturers  of  household  refrig- 
erators re-designed  their  product  on  the  basis  of  multiple  in- 
sulation on  the  incorrect  theory  that  each  layer  of  material 
in  the  walls  of  a  refrigerator  sets  up  or  offers  its  own  indi- 
vidual surface  resistance  to  the  transfer  of  heat,  even  though 
these  layers  are  laid  one  against  another  or  in  positions  of  in- 
timacy and  their  surfaces  are  not  exposed  to  the  surrounding 
atmosphere.  In  other  words,  in  theory,  the  surface  resistances 
of  many  layers  of  material  were  incorrectly  combined  to  arrive 
j  at  a  wholly  fictitious  high  total  resistance  of  a  given  wall  to 
[  the  infiltration  of  heat.  The  claim  of  superiority  based  on 
I  multiple  walls  of  insulation  was  a  familiar  one,  and  for  too 
•  many  years  unsuspecting  householders  counted  the  layers  in 
comparing  prices. 

With  the  growth  of  the  ice  industry,  the  refrigerator  in- 
dustry   expanded    proportionately,    and    competition    became 
keen  and  difficult.    Little  real  attention  was  paid  to  the  actual 
:  insulating  qualities  of  a  household  refrigerator ;  for,  as  some 
["have  said,  "the  ice  man  wanted  to  sell  ice,  the  refrigerator 
manufacturer  wanted  to  sell  refrigerators,  and  the  householder 
'  wanted  something  low  in  cost  and  high  in  hopes."    It  is  prob- 
ably more  to  the  point,  however,  that  the  real  need  for  bet- 
ter insulation  in  household  refrigerators  had  never  been  made 
clear  to  the  ice  man,  the  refrigerator  builder,  or  the  house- 
holder.    In  a  word,  the  necessity  did  not  exist,  and  the  need 
was  not  understood. 


342  CORK  INSULATION 

Nevertheless,  the  more  progressive  refrigerator  manufac- 
turers and  the  more  progressive  producers  and  distributors  of 
ice,  often  in  cooperation  with  various  United  States  Govern- 
mental agencies,  State  Universities^  and  a  few  private  experi- 
mental laboratories,  kept  up  a  constant  if  not  intensive  search 
for  more  practical  and  accurate  information  on  the  applica- 
tion of  refrigeration  principles  and  appliances  in  the  home 
New  and  better  sanitary  refrigerator  linings  were  developed, 
air  circulation  was  ^•astly  improved,  shelves  were  rearranged 
to  accommodate  various  foods  in  the  position  in  the  refrig- 
erator where  they  would  keep  best,  better  hardware  was 
adopted,  doors  were  sealed  with  improved  wick  gasket,  drain  ! 
pipes  were  placed  so  as  to  permit  of  ready  removal  and  clean- 
ing, ice  compartments  were  enlarged  to  an  adequate  size, 
outside  icing  doors  were  provided  for  the  discriminating,  and 
better  exterior  finishes  were  offered.  Very  little  attention, 
however,  was  paid  to  the  insulation  of  what  would  other- 
wise have  been  a  perfect  masterpiece  of  craftsmanship.  A  few 
manufacturers,  among  them  those  using  solid  porcelain  lin- 
ings, adopted  granulated  cork  as  the  insulating  medium;  but 
as  refrigerators  were  not  then  sold  on  the  basis  of  compara 
tive  permanent  efficiency  of  operation  in  service,  the  added 
value  of  the  ground  cork  insulation  was  not  generally  appre- 
ciated even  by  those  manufacturers  who  used  it. 

154. — The  Advent  of  the  Household  Refrigerating  Machine 
and  Early  Trials  with  Pure  Corkboard  in  Household  Refrig- 
erators.— It  has  been  seen  that  the  practice  of  cooling  food  and 
dfink  below  the  temperature  of  the  atmosphere  by  the  use 
of  snow  and  ice  was  followed  for  many  centuries  before  natural 
ice  came  to  be  stored  in  caves,  in  ice  pits,  and  then  in  ice 
houses,  and  that  within  the  present  generation  means  were 
perfected  for  the  manufacture  of  ice  in  commercial  quantities 
for  refrigeration  purposes.  Now  we  observe  that  within 
scarcely  the  past  dozen  years  attention  has  been  directed  tO; 
ways  and  means  of  producing  refrigeration  in  the  home  by 
mechanical  means  directly ;  but  it  is  only  since  the  World  War 
that  the  household  machine  has  been  manufactured  in  quan- 
tities and  proven  a  success,  the  production  during  recent  years 
having  been  about  as  follows : 


CORKBOARD  INSULATED  REFRIGERATOR  343 

Prior    to 1923 20,000 

Year    1923 25,000 

Year   1924 50,000 

Year    1925 100,000 

Year    1926 500,000 

Estimated    1927 750,000 

At  present  the  subject  of  household  refrigeration  is  receiv- 
ing the  attention  of  many  inventors  and  engineers,  as  well  as 


FIG.   160.— TYPICAL  AIR-COOLED  HOUSEHOLD  REFRIGERATI.NG  MACHINE. 

of  several  hundred  manufacturers.  New  and  improved  me- 
*i  chanical  devices  and  processes  are  being  de\eloped  almost 
!  constantly,  several  editions  of  a  complete  treatise  on  "the 
principles,  types,  construction,  and  operation  of  both  ice  and 
I  mechanically  cooled  domestic  refrigerators,  and  the  use  of 
j  ice  and  refrigeration  in  the  home."  having  already  been  pub- 
I  lished,*  under  the  title  of  "Household  Refrigeration,"  by  H.  B. 
[.   Hull,  Refrigeration  Engineer. 

Mr.  Hull,  in  introducing  his  subject,  says  that,  "mechan- 
ical household  refrigeration  is  having  an  important  influence 
on  refrigerator  cabinet  construction  ;  it  is  necessary  to  have 
better  constructed  and  insulated  refrigerators  to  operate  satis- 
factorily, with  the  lower  food-compartment  temperatures  pro- 
duced by  the  mechanical  unit" ;  and  Mr.  Hull  drew  extensively 
on  his  experience  as  a  refrigeration  and  research  engineer, 
and  in  turn  upon  the  work  and  experience  of  many  others  in 
allied  industries,  in  setting  forth  his  conclusions  with  respect 

*.\ickerson    &    Collins    Co.,    Publishers,    5707    West    Lake    Street,    Chicago,    Illinois. 


344  CORK  INSULATION 

to  the  insulation  of  mechanically  cooled  household  refrig- 
erators. 

It  was  little  suspected,  perhaps,  in  the  beg-innings  of  me- 
chanical refrigeration  for  the  home,  that  serious  trouble  would 
be  experienced  with  the  operation  of  the  household  refrig- 
erator itself;  because  there  was  then  enough  real  and  poten- 
tial trouble  with  the  mechanical  unit,  without  contemplating 
trouble  from  a  coordinated  product  manufactured  by  others, 
especially  since  household  refrigerators  had  been  successfully 
produced,  sold  and  used  in  the  home  for  a  great  many  years. 
Yet  serious  trouble  there  was,  and  it  took  a  lot  of  time  and 
much  money  to  eliminate  it. 

A  dozen  years  or  so  ago  (about  1915),  there  was  need 
for  better  insulation  in  household  refrigerators,  but  the  neces- 
sity for  it  did  not  then  exist;  and  it  was  not  until  a  serious 
attempt  was  made  to  cool  such  refrigerators  by  mechanical 
means  that  the  subject  of  enough  permanently  efficient  in- 
sulation was  made  a  research  and  engineering  consideration. 
The  cost  of  operating  one  of  the  early  makes  of  mechancially 
cooled  domestic  refrigerators,  original  investment  ignored, 
was  frequently  somewhat  greater  than  the  cost  of  cooling  the 
same  refrigerator  with  ice.  The  much  lower  temperature  that 
could  be  maintained  by  the  mechanical  unit  was  consequently 
featured  "as  its  greatest  advantage,  and  the  plant  was  adjusted 
and  sold  on  that  basis.  Thereupon  the  refrigerator  usually 
began  to  leak,  and  frequently  to  smell,  and  then  the  motor 
was  observed  to  operate  a  greater  number  of  hours  per  day, 
until  it  was  sometimes  said  to  operate  almost  continuously, 
and  general  dissatisfaction  with  the  installation  on  the  part 
of  the  purchaser  was,  under  such  conditions,  the  inevitable 
result. 

Examination  of  these  "leakers"  and  "smellers"  usually 
revealed  the  fibrous  insulation  in  the  hollow  walls  of  the  re- 
frigerator water-soaked  and  odor-saturated ;  whereupon,  after 
a  considerable  lapse  of  time  and  following  much  investigation, 
the  insulation  specifications  were  changed,  and,  borrowing  a 
page  from  the  experience  and  practice  of  commercial  cold 
storage  plants,  pure  corkboard  was  directed  to  be  used.  The 
permanent  insulating  efficien.cy  of  corkboard  in  cold  storage 
structures  was  a  known  quantity,  and  its  well-known  freedom 


CORKBOARD  INSULATED  REFRIGERATOR  345 

from  capillarity  was  expected  to  rid  the  correctly  insulated 
mechanical  refrigerator  of  the  water  conditions  so  consistently 
encountered  theretofore.  Unfortunately,  however,  the  question 
of  the  manner  and  method  of  installing  the  corkboard,  with 
respect  to  the  refrigerator  as  a  finished  unit,  was  virtually 
left  to  the  discretion  of  the  superintendent  of  the  plant  pro- 
ducing the  refrigerators;  and  it  was  but  natural  for  him  to 
cut  the  corkboards  to  fit  easily  into  generous  wall  spaces,  and 
in  other  respects  to  do  with  the  corkboard  just  about  as  had 
always  been  done  with  other  kinds  of  insulation  in  the  many 
years  preceding  the  advent  of  the  household  refrigerating 
machine. 

The  results  were  almost  as  unsatisfactory  as  they  had 
been  with  other  kinds  and  forms  of  insulation.  Leakers  and 
smellers  continued  to  be  the  order  of  the  day,  and  the  insu- 
lating efficiency  was  below  that  to  be  expected  with  cork- 
I  board  as  the  insulating  material.  Perhaps  the  refrigerato'- 
did  not  leak  half  as  much,  or  smell  quite  as  badly,  or  run 
■  nearly  as  long,  as  formerly,  with  other  kinds  of  insulation  ; 
but  it  leaked,  and  it  gave  off  odors,  and  it  cost  too  much  to 
operate ;  and  these  things,  coupled  with  the  usual  run  of 
mechanical  troubles  incident  to  the  development  of  a  new 
device,  were  enough  to  discourage  much  less  courageous  man- 
ufacturers than  those  who  blazed  trails  for  the  present-day 
mechanical  unit. 

If  a  glass  pitcher  of  ice  water  is  placed  on  a  kitchen  talkie, 

it  will  "sweat,"  under  usual  conditions  of  humidity,  such  an 

amount   that   the   water  of  condensation   will   sometimes   run 

on  to  the  table  top,  although  usually  it  will  evaporate  away 

I  almost   as   rapidly   as   it   forms ;   and   just   as   water   vapor   in 

;  suspension   in   the   surrounding  air  of  the   kitchen   would   be 

••'precipitated  on  the  cool,  outer  surface  of  the  glass  pitcher,  so 

would  water  vapor  have  been  precipitated  or  condensed  at  the 

same  rate  on  the  outer,  exposed  surface  of  the  interior  lining 

of  a  refrigerator  cooled  to  the  same  degree  by  ice  and  located 

in  the  same  kitchen. 

If  salt  is  added  to  the  pitcher  of  ice  water  and  stirred,  to 
reduce  the  temperature  of  the  mixture,  the  sweating  will 
usually    exceed   the    evaporation   by    such    an    amount    as    to 


346 


CORK  INSULATION 


quickly  form  a  puddle  of  water  on  the  table  top;  and  just  as 
water  vapor  in  suspension  in  the  surrounding  air  of  the 
kitchen  would  be  precipitated  on  the  cold,  outer  surface  of 
the  pitcher  containing  the  low  temperature  mixture,  at  a  rate 
too  rapid  to  permit  of  its  being  evaporated  away  as  fast  as 
it  formed,  so  would  water  A'apor  have  been  condensed  at  the 
same  rate  on  the  outer,  exposed  surface  of  the  interior  lining 
of  a  refrigerator  chilled  to  the  same  degree  by  a  mechanical 
household  refrigerating  machine. 


FIG.   161.— THE   SWEATING   PITCHER  OF    ICE    WATER  POINTED   THE   WAY 

TO   THE   PROPER   APPLICATION   OF   CORKBOARD  IN 

HOUSEHOLD  REFRIGERATORS. 


In  either  case,  the  only  difference  between  the  action  of 
the  pitcher  and  that  of  the  refrigerator  would  be  in  the  rate 
of  evaporation  of  the  condensed  water;  evaporation  from  the 
surface  of  the  pitcher  would  be  more  rapid  than  from  the 
exposed  surface  of  the  interior  lining  of  the  refrigerator, 
because  there  would  be  greater  freedom  of  air  currents  about 
the  pitcher  than  there  would  be  about  the  confined  interior 
refrigerator  lining. 

The  foregoing  explains  why  the  mechanically  cooled  house- 
hold refrigerator  frequently  "leaked,"  and  why  the  former ; 
ice-cooled  domestic  refrigerator  rarely  if  ever  gave  evidence 
of  the  same  defect ;  the  rate  of  condensation  of  water  vapor 
in  the  case  of  the  mechanical  refrigerator  was  considerably 
greater  than  the  rate  of  evaporation,  whereas  the  rate  of  con- 
densation in  the  case  of  the  ice-cooled  refrigerator  was  usually 


CORKBOARD  INSULATED  REFRIGERATOR  347 

no  greater  and  was  frequently  less  than  the  rate  of  evapora- 
tion. Then,  too,  in  the  case  of  an  ice-cooled  refrigerator, 
moisture  condensed  out  of  air  entrapped  within  the  walls  of 
the  refrigerator  would  usually  be  in  intimate  contact  with 
the  insulation  in  such  walls,  and  would  be  absorbed  by  it  if 
the  insulation  possessed  capillarity  in  any  degree  whatever. 

j  Water,  as  is  well  known,  is  very  susceptible  to  tainting; 

i  a  glass  of  water  standing  on  a  dining-room  table  will  pick  up 
odors  at  a  rapid  rate,  and  become  unfit  for  human  consump- 
tion. Place  a  glass  of  water  on  a  kitchen  table  during  the 
preparation  of  a  meal,  and  two  hours  later  the  water  will  have 
an  odor.  The  water  of  meltage  coming  from  an  iced  refrig- 
erator has  an  odor;  because  as  the  air  in  the  refrigerator  cir- 
culates over  the  melting  ice,  the  water  of  meltage  extracts 
the  food  odors  and  carries  them  away  through  the  refrigerator 
drain.  Condensed  water  on  the  back  of  an  exposed  interior 
lining  of  a  refrigerator  will  quickly  become  foul,  by  absorption 
of  odors  from  the  air ;  and  thus  we  have  the  explanation  for 
the  so-called  "cork  odor"  in  the  structure  of  the  early  mechan- 

I  ically  cooled  household  refrigerator  insulated  with  corkboards 
so  loosely  installed  as  to  leave  the  exterior  surface  of  the 
interior  lining  exposed.     For  unless  some  material  with  a  cer- 

[    tain   heat    insulating   value   is   in    intimate    contact   with    the 

I  entire  outer  surface  of  a  refrigerator  lining,  such  surface  must 
be  thought  of  and  dealt  with  as  being  exposed  to  the  sur- 
rounding atmosphere,  at  least  in  so  far  as  the  condensation 

I   of  moisture  on  its  face  is  concerned. 

1  Odors  within  the  food  compartment  of  a  mechanical  re- 
frigerator are  usually  accounted  for  by  the  foods  stored,  or  by 

j  odors  coming  in  through  dry  bell-trap  or  goose-neck  of  the 
drain  pipe  from  which  all  water  has  evaporated.  An  ice- 
cooled  refrigerator  is  constantly  at  work  to  keep  its  air  purified, 
by  absorption  of  odors  by  the  water  of  meltage  and  discharge 
to  drain ;  but  a  mechanically-cooled  refrigerator  frequently  has 
little  or  no  water  of  meltage,  and  other  provision  must  be  made 
for  the  purification  of  its  air.  This  has  been  variously  accom- 
plished  by   ventilation   through   dry   drain   pipe,   where   such 

,  pipe  terminates  low  enough  to  escape  the  odors  from  the 
refrigerating  machine,  by  ventilation  through  loosely  fitted 
doors,  and  bv  still  other  means  entirely.     These  items  do  not 


348  CORK  INSULATION 

come  within  the  scope  of  the  subject  of  the  proper  insulation 
of  a  refrigerator,  but  they  are  touched  upon  here  because 
insulation  was  frequently  and  erroneously  blamed  for  such 
interior  odors  in  the  days  of  the  early  trials  at  insulating 
household  refrigerators  with  corkboard. 

155. — The  Modern  Corkboard  Insulated  Household  Re- 
frigerator.— Early  ice  storages,  ship's  cold  stores,  cold  storage 
houses  and  breweries  were  insulated  with  air  spaces  and  loose 
fill  materials  in  hollow  walls  with  reasonable  success,  all 
things  considered,  during  the  days  when  ice  was  employed 
as  the  refrigerant.  The  advent  of  mechanical  refrigeration 
and  lower  temperatures  in  cold  stores  increased  the  condensa- 
tion of  moisture  within  the  air  spaces  and  the  loose  fill  insu- 
lating materials  to  such  a  degree,  however,  as  to  frequently 
destroy  the  insulating  capacity  of  the  walls  entirely.  For  it 
will  be  recalled,  from  an  elaboration  of  the  subject  in  the 
chapter  on  "Measurement  of  Heat,  Change  of  State,  and 
Humidity,"  that  the  capacity  of  air  to  absorb  and  hold  moist- 
ure, or  water  vapor,  in  suspension,  varies  with  its  temperature ; 
and,  warm  air  being  capable  of  holding  more  moisture  than 
cold  air,  when  warm  air  is  cooled,  its  moisture  capacity  is 
lowered  until  a  temperature  is  reached  at  which  the  air  can 
no  longer  hold  all  of  its  moisture  in  suspension,  which  point 
is  the  point  of  saturation,  or  the  dew  point.  By  insulating 
the  exposed  surfaces  of  cold  stores  with  a  sufficient  thickness 
of  a  material  having  its  air  content,  upon  which  it  must 
depend  for  its  heat  retarding  properties,  divided  into  an  in- 
finitesimal number  of  microscopic  or  colloidal  particles  dis- 
persed throughout  the  material  in  hermetically  sealed  cells, 
so  that  such  air  loses  its  normal  properties  as  air,  the  precipita- 
tion of  water  vapor  within  such  insulation  or  within  the  build- 
ing structure  back  of  the  insulation,  due  to  exposure  of  chilled 
surfaces  to  the  atmosphere,  was  eliminated.  Pure  corkboard 
was  the  insulating  material  that  met  these  conditions,  both  in 
theory  and  practice,  when  properly  manufactured  and  when 
properly  applied  in  intimate  contact  with  the  surfaces  to  be 
insulated. 

Borrowing  another  page  from  the  experience  and  practice 
of  commercial  cold  storage  plants,  through  the  advice  of  a 


CORKBOARD  INSULATED  REFRIGERATOR 


349 


trained  insulation  engineer*  of  recognized  experience  and 
responsibility,  pure  corkboard  was  directed  to  be  applied  in 
mechanically  chilled  household  refrigerators  in  a  manner  that 
would  absolutely  eliminate  air  pockets  or  air  spaces  of  any 
kind  between  the  corkboard  and  the  outside  surface  of  the 


FIG.     162.— SEEGER    MODEL    SHOWING    PURE    CORKBOARD    APPLIED    IN 

ASPHALT  CEMENT  TO  INTERIOR  ONE-PIECE  ENAMELED-STEEL 

REFRIGERATOR  LINING,  WITH  ALL  AIR  EXCLUDED. 

interior  refrigerator  lining;  for  otherwise  water  vapor  in  that 
air  would  be  condensed,  due  to  its  contact  with  the  cold 
exterior  surface  of  the  lining,  the  partial  vacuum  created  by 
such  cooling  and  condensing  would  be  balanced  by  the  infil- 
tration of  additional  air  carrying  water  vapor  in  suspension, 
which  fresh  supply  of  air  would  in  turn  be  cooled  and  give  up 

*PUBLISHER'S    NOTE— The    author   of    this    book    is   credited   with    formulating 
the  suggestions  that  led  to  a  solution  of  the  problems  touched  upon  here. 


350 


CORK  INSULATION 


water,  and  the  c}cle  continued  so  long  as  the  refrigerator 
was  in  serxice.  A  certain  type  of  refrigerator,  having  an  opal 
glass  panel  lining,  and  usually  produced  by  skilled  cabinet- 
makers, escaped  almost  completely  the  difficulties  with  me- 
chanical household  refrigeration  that  were  experienced  by 
manufacturers  of  refrigerators  having  the  one-piece  enameled 
steel  linings.  The  wall  construction  of  such  refrigerators 
consisted  of  exterior  oak,  paper,  corkboard  tightly  compressed 


FIG.   163.— CABINETMAKER'S  INSULATION  DETAILS  FOR  REFRIGERATOR. 

into  position  in  intimate  contact  at  every  point,  paper,  wood 
sheathing,  and  a  thin  pad  of  builder's  felt  against  which  the 
opal  glass  paneled  interior  lining  was  secured.  One  of  the 
first  demands  placed  on  the  mechanical  household  refrigera- 
tion industry,  however,  was  for  a  very  much  reduced  cost  of 
the  assembled  refrigerator  units;  and  the  cabinet  type  of  cork- 
board  insulated  refrigerator  with  opal  glass  paneled  lining, 
which  was  virtually  a  cabinetmaker's  product  and  which  did 
not  readily  lend  itself  to  quantity  production,  was  soon  aban- 
doned in  favor  of  the  one-piece  enameled-steel  lining  type  of 
refrigerator. 

The  outside  or  back  of  an  enameled  steel  lining  does  not 
present  a  level  surface,  and  from  desire  to  have  sanitary 
corners  within  the  food  compartment  the  corners  were  round- 


CORKBOARD  INSULATED  REFRIGERATOR 


351 


ed.  Early  types  of  enameled  steel  linings  were  L-shaped, 
necessitating  a  separate  galvanized  iron  section  or  lining  to 
accommodate  the  mechanical  cooling  unit  and  to  be  fitted  into 


t 


-CABINETMAKER  PLACING    CoRKl 
BETWEEN    DOOR   oi' 


-IILFS   AND  RAILS 


the  crook  of  the  L  as  best  as  possible  and  insulated  from  it. 
The  corkboard  insulation  had  to  be  built  around  the  lining, 
obviously,  instead  of  the  insulation  being  installed  in  the 
refrigerator  v^-alls  and  the  lining  fitted  in  place  afterwards. 
Therefore,  the  use  of  some  waterproof,  odorless,  elastic,  highly 
cementations  material,  plastic  at  workable  temperatures  and 
solid  at  ordinary  temperatures,  a  material  reasonable  in  cost 
and  easily  obtained,  had  to  be  found  in  which  to  lay  up  or  set 
the  corkboards  in  position  against  the  exterior  of  the  refrig- 


FIG.  165.— (LEFT)  L-SHAPED  REFRIGERATOR  LINING,  DIFFICULT  TO 

INSULATE.— (RIGHT)  RECTANGULAR  REFRIGERATOR  LINING, 

EASY  TO  INSULATE. 

erator  linings.  After  repeated  trials  with  many  materials,  an 
unfluxed  petroleum  asphalt  of  suitable  characteristics  and 
mixed  with  a  certain  preparation  of  cork  flour,  as  described  in 
the  Articles  on  "Asphalt  Cement  and  Asphalt  Primer"  and 
"General  Instructions  and  Eciuipment,"  came  to  be  used  with 


352  CORK  INSULATION 

success,  and  such  method  of  application  of  corkboard  in  house- 
hold refrigerators  and  ice  cream  cabinets  came  to  be  known  as 
the  "hydrolene  process"*. 

The  equipment  for  the  proper  preparation  and  handling  of 
hot  Asphalt  cement,  in  the  refrigerator  manufacturing  plant,  must 
of  course  be  a  separate  consideration  with  each  manufacturing 
organization,  and  for  that  reason  no  attempt  will  be  made  here  to 
give  any  of  the  details  whatever.  A  word  of  caution  would 
probably  not  be  out  of  place,  however,  with  respect  to  the 
danger  from  fire.  This  is  probably  the  only  serious  manu- 
facturing objection  to  the  Asphalt  cement  process  of  install- 
ing corkoard  in  household  refrigerators,  but  the  benefits  have 
been  of  so  great  an  importance  to  the  household  refrigeration 
industry  as  to  put  such  objection,  for  the  present  at  least,  in 
the  class  of  "necessary  manufacturing  evils."  The  properties 
of  asphalt  are  at  least  briefly  outlined  elsewhere  in  this  book, 
and  additional  information  should  be  available  from  reliable 
sources.  There  is  just  one  simple  rule  to  follow  with  respect 
to  the  asphalt  to  use;  namely,  start  with  the  correct  material 
(not  necessarily  the  most  expensive),  and  if  it  is  not  damaged 
by  overheating  in  the  process  of  applying  the  insulation,  the 
finished  refrigerator  construction  will  contain  the  correct  As- 
phalt cement  as  a  bonding  and  sealing  material. 

Thus  it  has  been  seen  how  corkboard  came  to  be  adapted 
to,  and  adopted  for,  the  insulation  of  household  refrigerators 
by  the  mechanical  household  refrigeration  industry,  through 
the  desirability  of  using  a  more  efficient  insulating  material 
to  reduce  costs  of  mechanical  operation,  and  an  insulating 
material  which  when  properly  applied  in  a  unit  to  be  mechan- 
ically cooled  would  obviate  the  condensation  of  moisture 
within  the  insulation.  Also,  competition  between  the  enor- 
mous ice  industry  and  the  fast  growing  mechanical  household 
refrigeration  industry  had  the  usual  effect  of  directing  attention 
to  the  comparative  cost  and  efficiency  of  the  two  systems  of  pre- 
serving foodstuffs  in  the  home.  Research  on  the  part  of  the  ice 
industry  is  said  to  have  made  the  important  discovery  that  with 
adequate  and  proper  corkboard  insulation,  with  improved  air  cir- 
culation, with  proper  i)]acement  of  foods,  and  other  considera- 


*Registered   by   Delco-Light   Company,   subsidiary  of   General   Motors   Corporation, 
Dayton,   Ohio,   manufacturers  of  Frigidaire  Electric  Refrigeration. 


CORKBOARD  INSULATED  REFRIGERATOR 


353 


1 

.]\^.„..„,J. 

1 

11, 

y.. 

\r^^^^ 

ir^l 

\   11  1 

(HT^^ 


^~Ji 


k 


^ 


fB 


OlJ 


^ 


\ 


Jiy 


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FIG.    166.— AIR  CIRCULATION  IN  HOUSEHOLD   REFRIGERATORS. 


354 


CORK  INSULATION 


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FIG.    167.— AIR   CIRCULATION    IN   HOUSEHOLD   REFRIGERATORS. 


CORKBOARD  INSULATED  REFRIGERATOR  355 

tions,  an  ice  cooled  refrigerator  will  give  results  in  the  correct 
preservation  of  foods  in  the  home  that  cannot  be  expected  with 
mechanically  cooled  refrigerators.  Then,  too,  some  of  that  great 
fraternity  of  refrigerator  manufacturers  not  identified  with 
the  mechanical  household  refrigeration  industry,  wished,  for 
the  most  part,  to  have  their  products  adaptable  to  either  sys- 
tem of  refrigeration, — ice  or  mechanical, — and  therefore  ad- 
justed their  insulation  specifications  to  meet  the  most  exacting 
requirements. 

Household  refrigeration  and  the  proper  insulation  of  the 
household  refrigerator  are  today  important  correlated  sub- 
jects, and  their  importance  promises  to  continue  to  increase 
so  long  as  food  is  consumed  in  the  home.  The  National 
Association  of  Ice  Industries,  163  West  Washington  Street,  Chi- 
cago, Illinois,  has  equipped*  to  give  the  subject  of  refrigeration 
in  the  home  every  attention  and  consideration.  From  one  of  its 
many  interesting  and  valuable  publications  and  pamphlets,  this  is 
extracted : 

WE  GO  SHOPPING  FOR  A  REFRIGERATOR 

A  clever  woman  once  said  that  it  was  a  wise  girl  who  knew  good 
"husband-material"  when  she  saw  it!  And  it  is  a  wise  woman  who 
knows  a  good  refrigerator  when  she  meets  one,  for  here  beauty  is 
only  skin  deep  with  a  vengeance  and  it's  the  inside,  not  the  outside, 
of  an  ice  box  that  counts.  A  woman's  intuition  won't  help  her  much 
in  looking  at  it.  Nor  do  white  enamel  and  nickel  finishings  make  the 
refrigerator,   any   more   than   clothes   make   the   man. 

Rule  one,  in  a  case  like  this,  is  to  go  to  a  reliable,  intelligent 
dealer  and  buy  a  box  that  bears  the  name  of  an  established  builder 
of  refrigerators.  When  a  man  signs  his  output  with  his  own  name, 
he  is  apt  to  be  proud  of  it  and  to  do  a  good  job. 

The  main  points  to  look  out  for  in  choosing  a  refrigerator  to 
live   with   are   these: 

I  1.     Insulation:     How  are  its  walls  built? 

2.  Circulation:     Can  the  air  flow  freely? 

3.  Size:      Not   only   of  the   whole   box   in   relation   to 

the   size   of  the  family,  but  of  the   ice  compart- 
ment  in   relation   to  the   box  itself. 

4.  Drain  pipes  and  shelves:     Are  they  easy  to  adjust 

and  hard  to   rust? 

5.  Handles    and   corners :      Are   they   easy   to    turn    and 

easy  to  clean? 
What  and   Why  Is  Insulation^ — To  insulate  anything  is  to   cut   it 
off  from  its  surroundings,  make  an   island  of  it.     And  the   walls  and 


*  Household    Refrigeration    Bureau    of   the    National    Association    of   Ice   Industries, 
Dr.    Mary    E.   Pennington,   IDirector. 


356 


CORK  INSULATION 


interlinings  of  a  good  refrigerator,  the  doors  and  top,  should  cut  it 
off  from  the  warm  outside  air.  It's  not  fair  to  expect  100  pounds  of 
ice  to  cool  the  whole  outside  world!  So  a  poorly  insulated  refrig- 
erator, however  handsome  to  look  upon,  is  largely  an  ice-melting  plant 
that  wastes  ice  and  does  not  maintain  sufficiently  low  temperatures. 
The  ideal  is  to  have  a  hard-wood  case  about  ^-inch  thick  (oak 
is  best)  with  the  equivalent  of  at  least  two  inches  of  corkboard  be- 
tween this  and  the  inside  lining  of  porcelain.  The  "reason  why"  for 
this  is  that  such  an  interlining  not  only  keeps  heat  out,  but  it  will 
not  absorb  moisture,  and  is  rigid  so  that  it  will  not  sag  leaving  air 
spaces. 


FIG.   168.— WISE  WOMEN  KNOW  GOOD  RKKRIGERATORS. 

Merely  wood,  paper  and  air  will  not  keep  the  heat  out  of  the 
refrigerator,  such  walls  leave  the  ice  badly  handicapped  in  its  war 
with  outside  heat!  Ask  to  see  a  cross-section  of  the  refrigerator  walls. 
If  the  makers  are  proud  of  their  box,  they  will  be  glad  to  "show" 
you. 

On  these  protecting  walls  and  well-insulated  and  tightly  closing 
doors  depends  largely  the  coolness  of  the  food  compartments.  They 
should  average  20  to  26  degrees  colder  than  outside  the  refrigerator 
when  the  room  thermometer  reads  70  to  75°  F.  As  the  weather 
grows  colder,  this  difference  grows  less.  Under  the  ice,  the  coldest 
place,  the  thermometer  should  read  not  more  than  45°  F.,  and  on 
the  top  shelf  of  a  side-icer  or  on  the  bottom  of  a  top-icer,  the  tem- 
perature should  not  be  much  more  than  50°  F.  when  the  room  is 
70  to  75^  F. 

Circulation  Means  "Air  Move  On." — "Side-Icer  or  Top-Icer"?  That 
is  a  question,  too. 


CORKBOARD  INSULATED  REFRIGERATOR  357 

It's  the  cold  circulating  air  that  cools  the  foods.  To  be  sure 
that  you  are  getting  good  circulation,  look  to  see  that  there  is  a 
broad  unobstructed  drop  from  the  ice  chamber  into  the  food  com- 
partment. 

In  a  side-icer  there  should  be  a  solid  insulated  partition  between 
the  ice  chamber  and  the  food  compartments.  In  this  way  the  cold 
air  is  "baffled"  in  any  attempt  to  sneak  out  into  the  food  compart- 
ment. It  must  go  down  and  around,  collecting  heat  and  odors  from 
the  food  and  traveling  all  the  way  back  to  the  ice  chamber  to  be 
re-cooled  and  deodorized.  Good  circulation  is  necessary  to  dryness 
and  absence  of  odors,  as  well  as  to  evenness  of  temperature. 

Both  side-  and  top-icers  are  good  if  well  designed.  The  side- 
icer  is  often  more  convenient  to  ice;  and  the  top-icer  has  the  advan- 
tage of  a  broader  drop  for  the  cold  air  and  less  difference  between 
the  coldest  and  warmest  place  in  the  box,  but  the  average  tempera- 
tures are  about  the  same. 

Sice,  Too,  Is  Important. — Be  sure  that  the  refrigerator  is  big  enough 
for  the  family  needs,  not  only  in  winter,  but  in  the  good  old  sum- 
mer time  when  more  perishable  foods  are  used,  when  the  refrigerator 
must  work  harder  to  keep  the  temperatures  down  and  when  week- 
end guests  are  abundant.  Almost,  then,  you  need  elastic,  rubber  re- 
frigerators! So  buy  the  refrigerator  for  your  greatest  need,  not  your 
smallest    one,    remembering   it   won't    stretch. 

Also,  it  is  important  that  the  ice  chamber  be  the  right  size  in 
proportion  to  the  remainder  of  the  box.  It  should  occupy  about 
one-third  of  the  whole  inner  space  and  the  smaller  the  box,  the 
larger  the   relative  size  of  the  ice   chamber. 

Generally  speaking,  a  family  of  two  can  get  along  with  a  refrig- 
erator taking  fifty  pounds  of  ice.  For  the  average  family  of  four, 
100-pound  capacity  is   required. 

Drain  Pipes  and  Shelves. — "I've  missed  all  the  best  advantages  that 
came  my  way,"  said  the  blonde  spinster,  "because  I  had  to  go  home 
and  empty  the  pan  under  the  refrigerator."  Don't  have  a  pan!  Be 
sure  there  is  a  drain  pipe,  well  fitted  and  easily  disconnected,  with 
'a  good  water  seal  at  the  floor  so  that  it  lends  itself  gracefully  both 
to  cleaning  and  readjustment  without  danger  of  leakage.  This  small 
point  means  much  to  the  housekeeper's  serenity,  and  keeps  her  temper 
down,  though  not  so  important  in  lowering  refrigerator  temperature! 

Again,  the  blonde  spinster  needed  an  automatic  ice  man.  She 
got  him  by  having  an  outside  door  into  the  ice  chamber.  No  longer 
did  she  need  to  be  at  home  when  the  ice  man  came! 

Shelves  should  be  of  woven  steel  wires,  well  welded  to  steel 
bars,  so  that  they,  too,  are  easy  to  clean,  hard  to  rust,  and  will 
neither  slip  nor  sag. 


358  CORK  INSULATION 

Handles  and  Corners. — Round  corners  are  easier  to  clean  than 
square  ones,  but  if  you  have  more  time  than  money,  the  more  expen- 
sive round  construction  may  be  foregone.  It  is  worth  the  money, 
however,  to  be  sure  that  handles  are  heavy  and  close  the  doors  easily 
and  tightly.     No  use  to  buy  a  refrigerator  and  let  it  stand  open. 

Always  the  more  you  invest,  the  more  interest  you  draw.  The 
money  invested  in  a  really  good,  efficient  refrigerator  draws  big  in- 
terest in  appetizing,   wholesome   food,   economically   stored. 

HOW  TO  BRING  UP  A  REFRIGERATOR  IN  THE  WAY 
IT  SHOULD   GO. 

Refrigerators  must  be  properly  fed  and  taken  care  of  if  you  want 
them  to  do  you  credit.  Long  life  and  good  service  from  a  refrigerator 
are  dependent  on  points  like  these: 

Location. — Set  your  refrigerator  in  as  cool  a  place  as  possible. 
It  is  hard  on  the  refrigerator's  efficiency  to  put  it  for  your  convenience 
too  near  the  stove,  or  in  the  sun  for  the  ice  man's  pleasure.  Give  it 
a  fair  location — no  ice  box  craves  a  place  in  the  sun.  Fill  it  full  of 
ice  and  allow  it  twenty-four  hours  to  get  the  heat  out  of  the  box 
before  you  start  to  cool  foods. 

Feed  It  Plenty  of  Ice. — It  costs  less  in  the  end,  and  you  get  more 
for  your  money,  if  you  keep  the  ice  chamber  full.  Never  let  it  get 
more  than  half  empty.  When  there  is  only  a  small  piece  of  ice,  it 
has  more  to  overcome,  melts  more  quickly  and  you  pay  more  to  get 
back  to  the  necessary  low  temperatures  again. 

Cleanliness. — Cold  and  Cleanliness  are  the  two  slogans  of  food 
preservation.  Keep  dirt  from  getting  into  the  box  and  you  won't 
need  to  work  to  get  it  out.  An  ounce  of  prevention  is  worth  several 
pounds  of  cure  here.  This  means  washing  the  ice,  if  necessary,  be- 
fore it  goes  into  the  refrigerator,  wiping  off  milk  bottles,  washing 
lettuce,  etc. 

Have  the  proper  kind  of  containers  to  put  the  food  in,  to  save  , 
space,  permit  proper  circulation  and  prevent  spoilage  and  "spillage." 
There  are  enamel  and  glass  containers,  with  and  without  tops,  and , 
attractive  nests  of  bowls  to  be  had  at  varying  prices  to  suit  all  purses. 
The  many  glass  bottles  with  screw  tops  that  foods  come  in  these 
days  make  perfect  and  economical  containers  for  food  storage. 

With  these  precautions  there  will  be  no  need  to  heat  up  the 
refrigerator  by  giving  it  hot  baths.  Wfipe  it  out  with  cold  water 
and  sal  soda  (one  tablespoon  to  four  quarts)  once  a  week.  Monday 
morning,  when  food  and  ice  are  low,  is  a  good  time  for  this,  or 
Friday  before  loading  with  ice  and  food  for  the  week-end. 

Dry  with  a  clean  cloth.  Work  rapidly  and  use  a  double  strength 
washing  soda  solution  of  cold  or  tepid  water  to  pour  down  the 
drain  to  remove  slime.  There  will  be  little  need  of  extreme  measures, 
of  long  brushes  or  the  use  of  hot  water,  if  foods  are  carefully  stored. 


CORKBOARD  INSULATED  REFRIGERATOR  359 

Clear  the  Way  for  the  Cold  Air. — Note  the  places  where  the  cold 
air  drops  from  the  ice  and  where,  when  warmed,  it  goes  back  to  the 
ice,  and  do  not  shut  them  off  by  stacking  food  in  these  spots.  Also, 
do  not  shut  off  the  air  passages  where  the  warmed  air  goes  up  and 
into  the  ice  chamber  again.  Air  currents  (good  circulation)  are  just 
as  necessary  to  efficient  refrigeration  as  is  insulation.  In  other 
words,  leave  air  spaces  between  everything  and  everything  else,  so 
that  the  cold  air  can  be  on  its  way.  When  the  inside  of  the  refrig- 
erator begins  to  look  like  a  sardine  can,  it  is  a  reproach  to  you. 

A  False  Economy. — Don't  wrap  the  ice  in  a  mistaken  effort  to 
make  it  last.  Ice  must  melt  in  order  to  cool.  It  takes  up  the  heat 
and  sacrifices  itself  to  serve  you.  Hoard  it  and  like  a  miser's  money 
it  can  do  you  no  good. 

Fair  Play. — Never  put  hot  foods  into  the  refrigerator.  This  is 
taking  an  unfair  advantage.  Cool  jellies,  soups,  custards,  etc.,  to  room 
temperature  before  putting  them  in  the  ice  box. 

Go  in  and  out  of  the  refrigerator  quickly  and  close  the  door 
behind  you  every  time.  Take  a  tray  and  remove  several  things  at 
once.  Every  time  you  carelessly  open  the  door  of  a  refrigerator  into 
a  hot  room,  you  cause  an  appreciable  increase  in  ice  meltage. 

156. — Typical  Details  of  Household  Refrigerator  Construc- 
tion.— It  would  be  impossible  to  illustrate  in  this  book  even  a 
fractional  part  of  the  many  makes  and  types  of  refrigerators 
manufactured  in  the  United  States,  and  for  that  reason  but  a 
very  few  of  them,  selected  at  random,  are  illustrated  and 
described*  in  this  Article : 

RHINELANDER    "AIRTITE"    REFRIGERATORS. 

Lini)ig. — One  piece  patented  porcelain  lining.  All  surfaces  are 
beautiful,  snow  white  porcelain  as  smooth  as  glass — no  cracks  or 
seams,  with  broadly  rounded  corners  at  top  and  bottom,  greatly 
simplifying  cleaning.  The  inside  linings  of  all  doors  are  full  porce- 
lain, pan  shaped,  in  keeping  with  the  beautiful,  snow-white  interior, 
j  Hardzmre. — Heavy    brass,    nickel    plated,    hand    buffed    hardware 

,^  used  throughout,  made  oversize  to  insure  extra  wear.     Self-acting  type 
lock  takes  immediate  action  and  holds  door  air-tight. 

Equipped  for  Ice  or  Mechanical  Refrigeration. — Ice  or  coil  chamber 
is  placed  inside  of  the  porcelain  lining,  instead  of  outside,  to  insure 
free,  unobstructed  circulation  of  cold  air  around  the  compartment  as 
well  as  through  it.  Many  models  are  equipped  for  ready  installation 
of  electric  refrigerating  unit.  Hanger  bolts,  and  capped  openings  in 
the  rear  near  top  of  ice  chamber,  are  standard  equipment  on  these 
models;    suitable    either    for    ice    or    mechanical    refrigeration.      Other 


*Descriptions  are  those  of  the  manufacturer,  and  are  to  be  accepted  only  for  what 
they  may  prove  to  be  worth. 


360 


CORK  INSULATION 


models,  for  ice  only,  have  extra-sturdy  ice  racks,  more  than  twice 
as  strong  as  necessary,  made  from  heavily  coated  galvanized  steel, 
with  galvanized  iron  baffles  in  ice  compartment  to  direct  air  cir- 
culation. 

Shelves. — Rhinelander  shelves  are  woven  in  our  factory,  electrically 
welded,  and  then  heavily  coated  with  tin  giving  a  clean,  bright  and 
lasting  finish.     Shelves  designed  to  insure  free  circulation  of  air. 

Casters. — Ball  bearing  lignum-vitae  casters. 


FIG.    169.— DETAILS    OF    RHINELANDER    REFRIGERATOR    CONSTRUCTION. 


Insulation. — One  and  one-half  inch  pure  sheet  cork  compressed  in 
position  in  intimate  contact  with  waterproof,  saturated-felt  covered 
lining  surface,  and  sealed  in  with  special  waterproof  compound. 

Exterior. — Heavy  Airtite  solid  hardwood  construction.  No  thin, 
set-in,  sunken  panels.  Triple  coated  porcelain  or  natural  hardwood 
finish. 

Manufactured  by  Rhinelander  Refrigerator  Company,  Rhinelander, 
Wisconsin. 


CORKBOARD  INSULATED  REFRIGERATOR 


361 


McCRAY  RESIDENCE  REFRIGERATORS. 

Compartments. — Compartments  to  be  as  per  manufacturer's  stand- 
ard for  each  size. 

General  Constructio)i.— The  general  construction  shall  be  of  cork 
and  wood;  two  inches  of  100%  pure  cork-board.  Both  sides  sheathed 
to  approximate  thickness  of  four  inches. 

Exterior  Finish. — Exterior  finish  to  be  as  per  manufacturer's  stand- 
ard   for   model   selected.      (a)      Exterior    front,    top   and    two    ends    shall 


•'](; 


70.— McCRAY   HOUSEHOLD   REFRIGERATOR. 


be   covered   with    No.   20   gauge    sheet    steel    finished   in   white    lacquer. 

;i   Back  and  bottom  covered  with  No.  24  gauge  galvanized   sheet   iron. 

i'  (b)  Exterior  front,  top  and  two  ends  shall  be  finished  in  quarter- 
sawed  oak,  well  filled  and  varnished.  Back  and  bottom  to  be  finished 
with  13/16-inch  matched  yellow  pine,  well  painted. 

Interior  Finish. — The  interior  finish  of  food  compartments  shall 
be  lined  with  highest  grade  of  one-piece  porcelain  fused  on  steel.  Ice 
or  coil  compartment  shall  be  lined  with  No.  24  gauge  sheet  iron, 
finished  with  white  refrigerator  enamel. 


362  CORK  INSULATION 

Doors. — Door  fronts  to  be  as  per  manufacturer's  standard  for 
model  selected,  (a)  Door  fronts  shall  be  covered  with  lacquer  fin- 
ished pressed  steel  to  match  exterior  front  finish  of  refrigerator,  (b) 
Door  fronts  shall  be  of  five-ply  veneered  wood,  flush  panel  type, 
finished  to   match   exterior   front   of  refrigerator. 

Shelves. — All  refrigerators  shall  be  equipped  with  bar  steel  shelv- 
ing, electrically  welded,  heavily  tinned  and  easily  removable  for 
cleaning. 

Hardware. — All  hardware  shall  be  of  substantial  pattern  nickel 
plated  bronze.  All  fasteners  shall  be  of  self-closing  bar  or  roller 
type. 

Circulation  System. — Ice  or  coil  compartment  shall  be  on  left  top 
side  of  refrigerator,  well  bafifled  to  insure  good  circulation  of  cold 
air,  and  to  have   suitable  water-sealed  drain   pipe   to  outside   of  unit. 

Base  or  Foundation. — Refrigerators  to  have  wood  base  approxi- 
mately four  inches  high.  Ball  bearing  casters  to  be  supplied  where 
necessary. 

Special  Equipment. — Special  base  for  enclosure  of  automatic  re- 
frigeration machine  to  be  furnished  on  order  and  same  to  be  finished 
to  conform  with  body  of  refrigerator.  Hasps  for  locks  to  be  fur- 
nished on  order,  but  locks  will  be  furnished  by  others. 

Detailed  Specifications. — All  refrigerators  shall  be  constructed  of 
100%  pure  compressed  cork-board  insulation  and  thoroughly  kiln-dried 
lumber,  especially  selected  and  well  adapted  to  the  service  required.  The 
cork-board  insulation  shall  be  inserted  in  a  substantial  and  well  braced 
wood  framing,  all  seams  of  the  cork-board  to  be  sealed  with  odorless,  hot 
asphalt  cement,  each  side  then  covered  with  heavy,  waterproof,  odorless 
insulating  sheathing,  forming  sections  in  which  the  insulation  has  been 
hermetically  sealed,  ready  to  receive  finishing  sheathing  on  both  sides 
of  the  sections.  The  thickness  of  cork-board  insulation  shall  be  as 
indicated. 

The  finishing  sheathing  on  the  exterior  of  all  refrigerators  shall  be 
approximately  13/16-inch  thick  and  consist  of  suitable  material  to  give 
desired  exterior  finish. 

All  wood  surfaces  exposed  to  view,  which  are  to  be  finished  in 
natural  wood  or  stained  to  match  other  trim,  shall  be  well  sanded  and 
finished  with  one  coat  of  filler,  one  coat  of  shellac  and  two  coats  of  best 
refrigerator  varnish. 

Refrigerators  for  All  Purposes. — There  is  a  McCray  Refrigerator 
for  every  purpose,  the  result  of  37  years  of  experience. 

Manufactured  by  McCray  Refrigerator  Co.,  Kendallville,  Indiana. 

GIBSON   "ALL   PORCELAIN"  REFRIGERATORS. 

General  Description. — The  Gibson  "All  Porcelain"  refrigerators  are, 
without  doubt,  the  finest  in  the  country.  The  beautiful  exteriors  and 
interiors  of   dazzling   white   porcelain  are  immaculate,   sanitary  and  dur- 


CORKBOARD  INSULATED  REFRIGERATOR 


363 


able.  The  new  Gibson  cast  aluminum  door  frame  construction  (patent 
pending)  is  one  of  the  greatest  advances  that  has  been  made  in  refrig- 
erator construction  in  years.  It  prevents  warping  or  swelling  of  the 
doors  and  insures  many  years  of  added  life  to  the  refrigerator. 

Interior. — Three  models  are  equipped  with  galvanized  iron  lined  ice 
compartments  and  seamless  porcelain  provision  compartments.     All  other 


171.— GIBSON    REFRIGERATOR    DOOR    CONSTRUCTION,    SHOWING 
CORKBOARD  INSULATION. 


models  have  porcelain  lined  ice  compartments.  All  doors  are  lined  with 
porcelain  door  plates. 

Insulation. — The  Gibson  "All  Porcelain"  refrigerators  are  insulated 
with  100  per  cent,  pure  cork-board,  sealed  air-tight  with  hydrolene  cement 
and,  in  addition,  have  many  layers  of  waterproof  asphalt  saturated  char- 
coal sheathing,  insulating  felt,  and  polar  board.  The  insulation  and  wall 
construction  is  unexcelled  for  economy  of  ice  consumption  or  efficiency 
when  used  in  cmncc' '(^ii  wi'.h  electric  refrigeration. 

Hardzcare. — The  locks  and-  hinges  are  heavy  cast  manganese  bronze, 


364  CORK  INSULATION 

triple  nickel-plated  and  highly  polished.  The  doors  are  all  equipped  with 
Wirf's  air-tight  cushion  gaskets. 

Shelves. — The  new  Gibson  flat  wire  shelves  (patent  pending)  are 
used  in  all  models.  They  are  easier  to  clean  and  dishes  slide  on  them 
without  tippi^jg. 

Electric  Refrigeration.- — Leading  manufacturers  of  electric  ice  ma- 
chines have  approved  the  "Gibson"  for  use  with  their  machines.  Ice 
machine  bases  arc  carried  in  stock  for  Gibson  "All  Porcelain"  refrig- 
erators. The  Gibson  "All  Porcelain"  refrigerators  are  equipped  with 
hangar  bolts  and  sleeve  outlets,  so  they  are  suitable  for  present  ice  needs 
and   future  electric  refrigeration  requirements. 

All  Metal  Refrigerators. — A  line  of  Gibson  "All  Metal"  refrigerators 
have  an  outside  case  of  heavy  galvanized  steel  finished  in  white  enamel, 
with  other  attractive  features.  Gibson's  "One-Piece"  porcelain  line  of 
white  porcelain  lined  refrigerators  has  merited  great  favor. 

iManufaclured  by   Gibson   Refrigerator  Co.,  Greenville,   Michigan. 

SEEGER  ALL-PORCELAIN   REFRIGERATORS. 

Circulation. — A  major  feature  of  efficiency  in  the  Seeger  refrigerator 
— a  remarkaljlc  food,  ice  and  power  conserving  device,  whether  ice  or 
electrical  refrigeration  is  used — is  the  Seeger  system  of  air  circulation, 
the  original  "Siphon  System."  It  is  installed  only  in  Seeger  refrigerators 
and  accomplishes  the  successful  preservation  of  foods  and  the  necessary 
low   temperature  with   a  minimum   consumption   of   ice   or  electricity. 

The  Seeger  original  siphon  system,  briefly,  continuously  keeps  in  cir- 
culation, throughout  the  interior,  a  vigorous  current  of  air  that  is  dry 
and  clean,  and  keeps  the  refrigerator's  every  nook  and  corner  pure  and 
sweet    at   all    times. 

The  siphons  form  a  partition  between  the  ice  or  cooling  unit  cham- 
ber and  the  food  chambers.  The  cold  air — heavier  in  the  ice  or  cooling 
unit  chamber  than  in  the  food  compartments — continuously  sinks  to  and 
through  the  grate  beneath  the  ice  block  or  cooling  unit,  then  to  the 
slanting  deflector  plate  that  is  seen  beneath  the  grate.  Next  the  de- 
flector plate  projects  the  air  into  the  food  chamber.  In  the  food  cham- 
bers the  air  expands,  and  in  so  doing  consumes  any  and  all  heat  atoms 
that  are  existent  there,  and  picks  up  all  odors,  moisture  and  impurities. 

Finally,  the  siphons  draw  the  air  back  into  the  ice  or  cooling  unit 
chamber  where  all  the  odors  and  impurities  that  have  been  gathered 
up  are  condensed  and  drained  off  with  the  water  from  the  melting  ice 
or   cooling  unit.     So   long  as   any   ice  remains  the  circulation  continues. 

Insulation. — Seeger  all-porcelain  refrigerators  are  insulated  with  pure 
sheet  corkboard,  2  inches  thick  laid  between  four  sheets  of  waterproof 
paper. 

Interior. — The  new  seamless,  one-piece  porcelain  interior  is  made  in 
our  own  factories,  of  vitreous  porcelain  on  Armco  iron  and  is  in  one 
entire  piece,  including  food  chambers,  ice  chamber  and  drip  pan.  The 
corners  are  round  and  the  surface  is  guaranteed  non-chippable.     A  new 


I 


CORKBOARD  INSULATED  REFRIGERATOR 


365 


improvement  is  the  providing  of  fastenings,  as  part  of  the  interior  lining, 
for  the  hanging  of  electrical  refrigeration  units. 

Exterior. — The  exterior  is  of  the  same  vitreous  porcelain  as  the  in- 
terior and  is  finished  with  nickel-silver  (German  silver)  trimmings.  The 
porcelain  exterior  surface,  like  that  of  the  interior,  is  guaranteed  non- 
chippable. 


^ 


-SEEGER    ORIGINAL    SYPHON    SYSTEM    CORK    INSULATED 
REFRIGERATOR. 


Hardware. — Each  door,  large  or  small,  is  fitted  with  locks  and  hinges 
exactly  suited  for  each  refrigerator's  requirements.  All  locks  are  of 
solid  brass  and  of  roller  type,  fitted  with  non-breakable  springs. 
Where  rubber  covered  compression  gaskets  are  used,  the  hinges  are  of 
spring  brass  and  are  fitted  with  steel  bushings,  washers  and  pins.  Where 
no  gaskets  are   used,   the  hinges   are   solid  brass. 

Manufactured  by  Seeger  Refrigerator  Company,  St.  Paul,   Minnesota. 


366  CORK  INSULATION 

JEWETT   SOLID  PORCELAIN   REFRIGERATORS. 

Refrigerator  Principles. — Jewett  Solid  Porcelain  refrigerators  com- 
bine all  four  basic  essentials  by  which  the  true  value  of  any  refrigerator 
may  be  judged:  (1)  Absolute  sanitation,  without  which  no  refrigerator, 
regardless  of  its  other  features,  is  safe  as  a  storage  place  for  food;  (2) 
Efficient  insulation,  an  unseen  essential  which  really  determines  the  cost 
of  operating  the  freezing  unit  and  the  number  of  years  of  service  it  will 
render;  (3)  Perfect  circulation,  which  produces  dry,  crisp  air  in  the 
refrigerator  instead  of  a  damp,  mouldy  atmosphere ;  and  (4)  Durable 
construction,  without  which  a  refrigerator  soon  wears  out  and  is  a 
poor  purchase  no  matter  how  cheap  its  initial  price. 

TJie  Famous  Solid  Porcelain  Interiors. — It  is  unfortunate  that  the 
descriptions  of  refrigerator  linings  have  never  been  standardized  like 
the  nomenclature  of  bathroom  equipment.  "Jewett"  solid  porcelain  lin- 
ings are  moulded  from  selected  clays  with  a  highly  glazed  china  finish 
fused  on  the  surface  in  our  pottery.  All  other  so-called  "porcelain" 
linings  are  made  of  thin  sheet  metal  with  a  coating  of  enamel  painted 
or  baked  on  them.  There  is  just  as  vast  a  difference  between  them 
and  "Jewett"  linings  as  between  a  solid  porcelain  bathtub  and  an  enam- 
eled iron  one. 

These  solid  porcelain  linings  are  an  inch  and  a  quarter  thick  and 
even  without  the  super-insulation  that  surrounds  them,  these  crocks  alone 
would  store  up  the  cold  and  maintain  low  temperatures  more  uniformly 
than  most  complete  refrigerators. 

Insulation. — The  illustration  shows  the  construction  of  the  walls,  floors 
and  ceilings  of  "Jewett"  solid  porcelain  refrigerators.  The  aggregate 
thickness  is  S-Y%  inches,  which  is  almost  double  the  thickness  of  tTie 
wall  construction  used  in  any  other  refrigerator. 

The  exterior  case  is  of  solid  ash,  carefully  doweled  and  glued ;  next 
come  two  courses  heavy  waterproof  insulating  paper,  then  a  1-inch  sheet 
of  pure  cork,  then  two  more  courses  heavy  waterproof  insulating  paper, 
then  a  course  of  ^-inch  tongued  and  grooved  lumber,  then  \y^  inches 
more  of  pure  cork,  then  a  course  of  waterproof  insulating  paper,  then  the 
solid  porcelain  lining  1-^   inches  thick. 

Outside  of  the  two  courses  of  lumber  necessary  to  give  the  proper 
strength  and  rigidity,  the  insulation  of  the  "Jewett"  solid  porcelain  re- 
frigerator consists  entirely  of  pure  cork,  which  is  the  most  efficient  form 
of   insulation  known. 

Circulation. — A  dry  atmosphere  in  a  refrigerator  is  essential  for  the 
preservation  of  food.  In  a  refrigerator  with  poor  or  no  ciculation,  all 
things  are  damp,  moist  and  moldy.  Then  there  is  an  odor.  Dryness 
prevents  all  these  things. 

The  cold  air  ducts  and  warm  air  flues  in  the  "Jewett"  solid  porce- 
lain refrigerators  are  designed  to  take  advantage  of  the  well-known 
principle  that  cold  air  falls  and  warm  air  rises.  On  account  of  its 
greater  weight,  the  cold  air  descends  from  the  ice  compartment  into  the 
food   compartment  below,  and   forces  the  warmer  air  in   the  upper  part 


CORKBOARD  INSULATED  REFRIGERATOR 


367 


FIG.    173.— SECTION   OF  JEWETT   SOLID  PORCELAIN   REFRIGERATOR 
SHOWING  CORK  INSULATION. 


368  CORK  INSULATION 

of  the  opposite  compartment  over  on  to  the  freezing  unit  where  the 
heat,  moisture  and  odors  are  absorbed  by  condensation.  After  being 
cooled  and  purified,  the  air  again  descends  and  passes  through  the  re- 
frigerator back  to  the  ice  chamber,  thus  forming  a  vigorous  and  con- 
tinuous rotation  of  the  entire  atmosphere  in  the  refrigerator. 

The  design  of  the  "Jewett"  ice  compartment  is  radically  different  from 
the  type  prevailing  in  ordinary  refrigerators.  Being  suspended  in  the 
metal  rack,  the  freezing  unit  is  constantly  surrounded  by  air  and  the 
cold  air  falls  easily  from  all  the  sides  as  well  as  from  the  bottom. 

Exterior  Finish. — The  outer  case  is  made  of  thoroughly  seasoned 
brown  ash  carefully  doweled  and  glued.  Solid  ash  is  particularly  adapted 
for  refrigerator  purposes  because  it  is  less  affected  by  changes  of  tem- 
perature and  humidity  than  almost  any  other  wood. 

"Jewett"  refrigerators  are  made  in  three  standard  finishes.  Finish 
A — exterior  of  natural  color,  carefully  selected,  straight  grain,  brown 
ash  with  three  coats  of  varnish.  Finish  B — exterior  painted  with  five 
coats  of  white  enamel.  Finish  C — exterior  of  white  opaque  glass  7/16- 
inch  thick,  secured  with  heavy,  solid  nickel-silver  (not  nickel  plated) 
trim,   highly   polished. 

When  special  finishes  are  desired,  we  can  furnish  the  cases  with 
three  coats  of  flat  white  which  can  be  enameled  to  match  surrounding 
woodwork.  Or  we  can  build  the  exterior  of  any  wood  desir.ed  and 
finish  to   sample  or  ship  without  stain  for  finish  upon  installation. 

Hardware. — "Jewett"  refrigerators  have  always  been  famous  for  the 
quality  and  durability  of  their  hardware.  The  doors  are  secured  by  lever 
fasteners  that  close  automatically  with  the  slamming  of  the  door,  pre- 
venting the  condensation  (commonly  called  "sweating"),  swollen  jambs, 
etc.,  which  result  when  doors  are  not  tightly  closed. 

The  hardware  on  natural  or  grey  finish  "Jewetts"  is  solid  brass,  highly 
polished;  on  white  enamel  or  opaque  glass  finish  it  is  solid  nickel-silver 
(not  nickel  plated),  and  is  much  heavier  and  more  substantial  than  the 
hinges  and  latches  on  any  other  make  of  refrigerator. 

Doors. — No  matter  how  well  the  rest  of  a  refrigerator  is  built  if 
the  doors  are  light  and  poorly  insulated  or  do  not  fit  tight  it  cannot  be 
a  safe  and  efficient  storage  chest  for  your  food.  The  doors  on  a 
"Jewett"  are  heavy,  substantial  and  well  insulated.  They  are  made  of 
solid  ash  with  plain  exterior  faces;  no  veneer  to  peel  off;  no  moldings 
or  panels  to  catch  dust;  no  chance  that  they  will  warp  or  sag.  They 
have  heavy  %-inch  overlaps  on  all  sides  instead  of  the  usual  5^-inch 
or  J/^-inch  overlap  on  ordinary  refrigerators  and  this  permits  the  use 
of  a  heavy,  live-rubber  (not  fabric)  compression  gasket  which  makes 
the  doors  absolutely  air  tight. 

Shelves  are  constructed  of  ^-inch  rod  spot  welded  to  5/16-inch  cross- 
bars heavily  coated  with  pure  block  tin  after  fabrication.  These  shelves 
rest  on  ribs  moulded  into  the  porcelain  lining  and  are  easily  removable 
for   cleaning. 

Manufactured  by  Jewett  Refrigerator  Co.,  Buffalo,  New  York. 


CORKBOARD  INSULATED  REFRIGERATOR 


369 


REOL  "LIFETIME"  REFRIGERATORS. 

Construction. — Custom-built  to  endure.  Solid  frame-work  of  ash 
posts,  with  cross-members  of  equal  strength  and  durability.  Vertical 
posts  run  the  full  height  of  the  box  reinforced  at  bottom  with  pressed 
steel  angles.  Heavy  uiano-type  casters  are  set  into  lower  end  of  these 
posts.      Interlocking    joints,    rigidly    securing    the    cross    members    to 


IFIG.  174.— DETAILS  OF  CONSTRUCTION  OF  REOL  CUSTOM  BUILT  REFRIG- 
ERATOR— ARROWS   (3)   POINT  TO  CORKBOARD  INSULATION 
AND    (4)    TO   ASPHALT   CEMENT. 

the  vertical  members.  Glued  and  screwed  into  a  rigid  solid  foundation 
to  hold  the  balance  of  the  structure.  Cores  for  doors  milled  from  one 
solid  piece  of  ash,  made  so  that  they  will  fit  closely  and  not  warp. 
Rabbits  on  the  doors,  fitting  into  ledges  on  the  framework,  effectually 
diminishing  leakage. 

Insulation. — Two  inches  of  solid  sheet  cork,  fastened  securely  to 
the  framework.  Fits  close  at  all  sides,  forming  an  efifective  and  per- 
manent barrier  against  the  passage  of  heat,  and  protected  with  heavy 


370  CORK  INSULATION  , 

waterproof  coating.  Solid  insulated  doors,  with  extra  insulation  fill-  j 
ing  out  air  space  formed  by  vitreous  porcelain  lining.  Insulation  | 
extends  through  front  stiles  and  rails,  thus  eliminating,  to  a  large  { 
degree,  one  of  the  points  where  heat  leakage  is  most  evident  in  i 
ordinary  refrigerator  construction.  Insulated  baffle  board,  directing  j 
downward  the  flow  of  cold  air,  and  affording  complete  circulation  and  i 
even  temperatures  in  all  sections  of  the  food  compartment. 

Interior. — Extra  heavy,  one-piece  vitreous  porcelain  crock  fused  i 
on  heavy  rustless  Armco  iron,  with  corners  rounded  and  curved  lips  '< 
provided  at  front,  making  the  inside  sanitary  and  easy  to  clean.  Extra  ' 
heavy  interwoven  steel  wire  shelves,  rust-proof.  | 

Exterior. — Flush  hardwood  exterior,  with  sections  firmly  joined  \ 
together  to  form  one  solid  piece.  Top  set  flush,  making  a  smooth  ' 
finish.  Rounded  corners  at  top.  Heavy  and  substantial  hardware  i 
that  is  solidly  fastened  to  the  framework,  operates  easily  and  amply 
supporting  doors  when  open  or  closed.  Springless  latches  that  are  ; 
self-closing,  without  effort  or  slamming.  1 

Manufactured  by   Reol   Refrigerator   Co.,   Baltimore,   Maryland.       ! 

BELDING-HALL    "ALL    PORCELAIN    EXTERIOR" 

REFRIGERATORS.  \ 

Description. — Belding-Hall  all  porcelain  refrigerators  are  constructed  i 

with   porcelain    exterior   and   one-piece    seamless    porcelain   lined   ice   and  | 

provision  chambers.     Insulated  especially   for  mechanical   refrigeration.  ! 


FIG.   175.— CORNER   SECTION  OF  CORKBOARD  INSULATED  nELDING-IIALL 
REFRIGERATOR. 

Materials. — The  best  grade  of  18-gauge  Armco  Rust  Resisting  Ingot 
Iron  is  used  throughout.  The  lumber  used  in  the  construction  of  the 
walls  of  these  cases,  also  in  the  doors,  has  been  chosen  with  care  to 
avoid   swelling  from  climatic  changes. 

Insulation. — The  corner  section  illustration  shows  our  2-inch  cork- 
board   insulation,   and   all   joints   and   corners   are   filled   with   an   odorless 


CORKBOARD  INSULATED  REFRIGERATOR 


371 


pitch  which  prevents  air  leakage  as  it  seals  all  the  crevices  where  the 
cork  cannot  fit  absolutely  tight.  The  door  construction  is  identical  with 
the  walls  of  the  refrigerator. 

Hardware.— AM  locks,  strikes  and  hinges,  as  well  as  all  screws,  are 
heavy  solid  brass,  nickel-plated,  of  the  latest  and  most  efficient  design. 
The  trimming  around  the  doors  and  corners  of  the  refrigerator  is  heavy 
aluminum,   nickel-plated. 

Metal  Ice  Rack. — One  of  the  greatest  improvements  is  our  solid 
metal  ice  rack  for  which  we  claim,  and  the  trade  concedes,  many  points 
of  excellence.     Also,  our  new  air  trap. 

Manufactured  by  Belding-Hall  Electrice  Corporation,  Belding, 
Michigan. 


SCHROEDER  "THERMO  FLO"  REFRIGERATOR. 

Refrigerating    Unit. — The    Inman    Thermatic   unit   which   operates    on 
nature's  thermo-syphon  principle  is  described  in  detail  as   follows :     Tank 

TANK    B 


TANK   A 


(SU^ 


dH^ 


FIG.    176.— SCHROEDER    THERMO   EI  O    REFRIGERATOR  TANKS. 


B  fits  inside  of  tank  A  as  shown  in  the  illustration.  The  ice  is  placed 
in  tank  B  and  cold  water  is  poured  over  the  ice  until  it  reaches  the 
level  of  the  lower  row  of  holes  in  Tank  B.    As  the  colder  water  seeks  the 


372 


CORK  INSULATION 


CORKBOARD  INSULATED  REFk'IGERATOR 


Z72, 


lower  levels  this  immediately  creates  a  circulation  of  water  from  top  to 
bottom  of  ice  chamber.  This  circulation  is  maintained  as  long  as  there 
is  even  a  small  piece  of  ice  in  the  tank.  Tank  B  has  54-inch  corruga- 
tions vv^hich  increase  the  cooling  area  of  the  ice  compartment  from  2550 
to  7072  square  inches — or  nearly  three  times  the  area  of  a  flat  surface. 
As  the  ice  melts  the  over-flow  is  carried  off  through  a  row  of  holes  near 
the  top  of  one  side  of  tank  A.  Inasmuch  as  the  warmer  water  rises  to 
the  top  and  is  carried  off  through  these  holes,  the  coldest  water  always 
remains  in   the   refrigerating  unit.     The   over-flow   is  carried   off  through 


FIG.    178.— SCHROEDER   THERMO    FLO    REFRIGERATOR. 


a  drain  at  the  bottom  of  the  ice  chamber.  The  fact  that  it  utilizes 
water  as  a  refrigerant  in  addition  to  the  ice,  results  in:  (1)  Uniform  low 
temperature;  (2)  Practically  100%  efficiency  out  of  every  piece  of  ice; 
(3)   Economical   consumption   of   ice. 

Circulation  of  Air. — The  circulation  of  air  within  the  refrigerator  is 
'always  at  the  maximum  because  the  refrigerant  is  always  above  the 
insulated  baffle  plate  which  separates  the  ice  and  food  compartments. 
When  ice  alone  is  used  as  the  refrigerant,  the  circulation  of  air  dimin- 
ishes as  the  ice  melts  away  below  the  top  of  the  bafile  plate.  The  cir- 
culation of  air  is  a  highly  important  factor  in  maintaining  constant,  low 
temperatures. 

Insulation. — In  order  that  the  thermatic  unit  may  function  at  its 
highest  efficiency,  the  influence  of  outside  temperatures  and  air  currents 
must  be  field  to  a  minimum.  For  this  reason  2-inch  sheet  cork,  laid  in 
mastic   asplialt    is   used   in   all   walls  and   doors. 


374  CORK  INSULATION 

Top  Iccr. — The  Thermo  Flo  is  a  top  icer  due  to  the  thermatic  unit. 
This  feature  eHminates  the  customary  abuse,  by  the  housekeeper,  of 
putting  all  kinds  of   foods  in  the  ice  compartment. 

Reserve  Compartment. — The  reserve  compartment  above  the  food 
chamber  is  entirely  separate  from  the  rest  of  the  refrigerator.  It  is 
designed  to  hold  reserve  ice,  chipped  ice,  or  for  special  cooling  purposes. 
Its  drain  connects  with  the  main  drain  pipe. 

Exterior  Finish. — The  outer  cabinet  of  the  Thermo  Flo  refrigerator 
is  built  of  selected  ash,  and  reflects  the  skill  of  master  cabinetmakers. 
A  variety  of  finishes  including  white  and  gray  lacquer  are  furnished 
as  specified.  Only  high  grade  fittings  and  hardware  are  used.  Self- 
locking  door  handles  are  standard  equipment. 

Interior. — The  interior  is  finished  in  white  enamel  of  highest  quality. 
Three  shelves  in  the  food  compartment  are  made  of  heavily  tinned  wire. 

Humidity. — The  fact  that  the  Thermo  Flo  uses  both  ice  and  water 
results  in  just  the  right  amount  of  humidity  for  proper  food  preservation. 

Size. — The  Thermo  Flo  refrigerator  is  made  in  two  sizes,  the  50- 
Ib.  re-icer  and  the  75-lb.  re-icer,  requiring  75  lbs.  and  100  lbs.  original 
icing,  respectively.  The  50-lb.  re-icer  has  outside  dimensions  of 
33^x22^x52^  inches  and  a  food  compartment  capacity  of  6  cubic  feet. 
The  75-lb.  re-icer  has  outside  dimensions  of  38^x22^x52j/2  inches  and  a 
food  compartment  capacity  of  8  cubic  feet. 

Manufactured. — The  Thermo  Flo  refrigerator  is  manufactured  by 
the  same  organization  which  introduced  the  JaSeL  ice  box  and  the  Na- 
tional ice  chest — The  J-S  Refrigeration  Division  of  the  John  Schroeder 
Lumber  Co.,  Milwaukee,  Wisconsin. 

SERVEL  ELECTRIC  REFRIGERATION  FOR 
HOUSEHOLD  USE. 
Exterior. — The  Servel  new  steel  cabinets  are  constructed  of  espe- 
cially selected  "Armco"  steel  carefully  lead-coated  as  an  absolute  pro- 
tection against  rust.  The  steel  shell  is  given  two  applications  of  oil 
base  primer  coat,  after  which  the  ground  coat  is  slowly  and  carefully 
baked  on  under  a  low  temperature,  producing  a  finish  which  will  neither 
peel  nor  scale.  Next,  several  coats  of  genuine  white  Duco  are  applied, 
which  are  each  allowed  to  air  dry.  The  slow  process  of  air  drying, 
while  it  creates  an  additional  factory  cost,  produces  a  much  better  ap- 
pearing and  more  lasting  finish  than  can  ever  be  expected  under  artificial 
or   forced  drying. 

Interior. — The  porcelain  liners  are  of  the  box  type,  and  are  so  con- 
structed, with  double  lock  flanges,  that  bolt  holes  or  screw  holes  are 
entirely    eliminated   except   those    required    for   tank  and    shelf    supports. 


CORKBOARD  INSULATED  REFRIGERATOR 


375 


This  produces  an  absolutely  sanitary  liner  and  eliminates  all  chance  of 
flaking  of  the  porcelain  finish,  due  to  uneven  strain  such  as  results 
from  the  use  of  screws  or  bolts. 

Chilling  Unit. — The  chilling  units  are  of  tinned  copper  and  have 
front  panels  and  ice  cube  tray-fronts  of  genuine  porcelain. 

Insulation. — The  insulation  is,  of  course,  pure  compressed  corkboard 
thoroughly  impregnated  with  hydrolene,  U/i  inches  thick  on  top  and  sides 
on  the  S-5,  2  inches  thick  top  and  sides  on  the  S-7  and  S-10;  with  a 
3-inch  bottom   thickness   on  all   models. 


FIG.    179.— SERVEL    ELECTRIC    CORKBOARD    INSULATED    REFRIGERATOR. 

All  seams  in  the  corkboard  are  filled  with  hydrolene.  Waterproof 
paper  is  then  applied  over  the  corkl)oard  as  added  seal  against  air  leaks. 
The  insulation  is  applied  against  the  liner,  and  there  is  an  air  space  of 
from   34-inch  to  3^-inch  between  the  insulation  and  the  exterior  metal. 

Manufactured  by  the  Servcl  Corporation,  Evansville,  Indiana. 


i 


376 


CORK  INSULATION 


COPELAND    "DEPENDABLE"    ELECTRIC    REFRIGERATORS. 

Model. — No.  C-5-P;  60^/4  inches  high,  22  inches  deep,  28  inches  wide. 
(One  of  5  models  for  small  homes  and  apartments.  Also  two  styles  of 
mode!  No.  215,  with  machine  overhead  and  covered  with  hood  ;  also  four 
Copeland-Seeger  models.)     Construction,  rugged  and  accurately  mortised. 

Interior. — White,  vitreous  porcelain,  with  rounded  coves.  Ice  cube 
drawers  have  bright  metal  finish.  Ice  cube  cap.icity,  90  cubes,  or  6 
pounds   at   one    freezing.     Shelf    space,    7.64   square    feet ;    shelves,   woven 


I 


Cross  section  through  wnll  of  box  shoicing 

insulation — Solid  corkboard,  3-ply  wood 

•panel  and  water-proof ing felts 

-EXTERIOR  VIEW  AND  WALL  SECTION  OF  COPELAND  ELECTRIC 
REFRIGERATOR. 


wire,  retinned.     Food  storage  capacity,  5  cubic   feet.     Defrosting  receiver 
eliminates  drain  pipe. 

Insulation. — Two  inches  solid  corkboard,  walls,  top,  door  and  bottom, 
hermetically  sealed  and  moisture-proofed  by  special  hydrolene  treatment 
and  protected  by  all-metal  sheathing,  prevents  odors  and  deterioration. 

Exterior. — Exterior  finish,  white  pyroxylin  lacquer  on  steel.  Trim, 
bright  metal  molding.     Hardware,  extra-heavy  automatic. 

Refrigeration. — Efficient  %  horsepower  motor ;  quiet  operation,  well- 
designed  valves,  accurately  fitted  bearings,  high  grade  materials,  skilled 
workmanship,  exceptionally  fine  inspection,  most  efficient  of  its  kind 
Connects  with  electric  light  socket. 

Manufactured  by  Copeland  Products  Co.,  Detroit,  Michigan. 


CORKBOARD  INSULATED  REFRIGERATOR  Zll 

157. — Notes  on  the  Testing  of  Household  Refrigerators. — 

While  there  are  no  g-enerally  accepted  and  approved  methods 
for  the  testing  of  either  ice  or  machine  cooled  household  re- 
frigerators, and  \irtuall}'  all  tests  made  thus  far  are  subject 
to  considerable  interpretation  as  to  the  results  obtained.  }et 
nuich  progress  has  been  made  and  there  is  reason  to  expect 
that  some  suitable  and  satisfactory  standard  method  of  testing 
household  refrigerators  may  soon  be  arrived  at  and  be  gener- 
ally accepted  by  those  most  interested  in  the  su1:)ject. 

The  Chicago  Tribune  originall)'  published  some  data  and 
suggestions  by  Dr.  A\\  A.  Evans  for  a  practical  "Refrigerator 

'.  Score  Card,"  for  refrigerators  using  ice,  which  Forest  O.  Riek 
later  combined  with  data  from  various  sources,  including  the 
U.  S.  Bureau  of  Standards  and  the  Good  Housekeeping  Insti- 
tute,   to    produce    a    refrigerator    score    card    substantially    as 

I  follows : 

REFRIGERATOR    SCORE    CARD. 

Xame   of   manufacturer 

Name   or   other   method    of   designaling   refrigerator 

Te'it   Item  :  Perfect  Scot? 

1.  Temperature  of  food   cham'ier 45%  —  — % 

2.  Ice     economy 20  —  — 

3.  Humidity    8  

4.  Circulation    • 7  —  — 

5.  Interior    finish     12  —  — 

6.  Drainage     3  —  — 

7  Exterior   finish    5  —  — 

Total     lOOP'o  % 

EXPEAXATIOX  OF  SCORE'  CARD 

1.  Tciiipcralurc  Test — Standard  conditions  for  test  demand  rcfrig- 
I  erator  to  be  in  a  rooin  free  from  drafts  and  at  an  even  temperatnrc.  Box 
'  should  not  contain  food.  Door  ■should  not  be  oriened  except  when  taking 
:  readings.  Refrigerator  shoi.'d  be  thoroughh-  chilled  for  4S  hours  l)cfore 
I  making  test.  Have  the  ice  chamber  full.  Place  thermometer  in  the  ccn- 
"tcr  of  the  food  chamlier.     ^lake  twelve  readings  at  intervals  of  one  hour. 

Take  room  temperature  simultaneously.     Score  as   follows: 

SCORE    FOR   TEMPERATURE 

Temperature,  F  Rate 

40° 45 

45    43 

50    36 

55    23 

60    9 

over  60    0 

2.  Ice    Ecfliioiiiy. — Refrigerator   should   be   thoniugblx    chilled    for   48 


378  CORK  INSULATION 

hours  before  starting  test.     Weigh  ice  at  the  start  of  test  proper.     Weigh 
ice  left  at  termination  of  test  proper.     Obtain  data: 

(a)  Temperature  of  food  chamber  (t). 

(b)  Temperature  of  room  (T). 

(c)  Square  feet  of  surface  exposure    (S),  calculated  on  exterior  di- 
mensions. 

To  determine  Ice  Economy,  substitute  in  the  following  formula: 
IX  144 

R  = 

Sx  (T— t) 
where  R  is  the  rate  of  heat  transmission,  which  may  be  defined  as  the 
number  of  B.t.u.  that  pass  through  one  square  foot  of  surface  daily  when 
the  difference  between  the  surface  is  1°  F. ;  I  is  the  number  of  pounds 
of  ice  melted  daily;  144  is  the  B.t.u.  required  to  melt  one  pound  of  ice; 
S  is  the  surface  exposure;  T  is  the  average  atmospheric  temperature; 
and  t  is  the  average  temperature  of  food  chamber.     Score  as  follows : 

SCORE  FOR  HEAT  TRANSMISSION 
Value  for  R  Rate 

1.13 20 

1.63 18 

2.0O 16 

2.33 14 

2.66 12 

3.00 10 

3.33 8 

3.66 6 

4.00 4 

4.33 2 

4.66 1 

5.00 0 

3.  Humidity. — In  making  humidity  tests,  a  wet  and  dry  bulb  ther- 
mometer should  be  used.  Take  twelve  readings  at  intervals  of  one  hour. 
See  U.  S.  Bureau  of  Standards'  tables*  for  readings  calculated  upon  dif- 
ferences in  temperatures  of  wet  and  dry  bulb  thermometers.  Score  as 
follows : 

SCORE  FOR  HUMIDITY 
Humidity  Rate 

55  to  65% 8.0 

65  to  76     7.5 

45  to  55     7.5 

40  to  45      7.7 

75  to  80      6.4 

30  to  40     6.0 

80  to  85      4.8 

20  to  30      4.8 

85  to  95      2.4 

90  and  over 0.0 

20  and  under 0.0 

4.  Circulation  of  Air. — ^Credit  a  maximum  of  5  for  probability  that 
cold  air  will  readily  pass  from  the  ice  compartment  to  and  through  the 
food  compartment  and  back  again  to  the  ice.  If  ice  compartment  is 
ample,  credit  2.  If  doors  do  not  fit  snugly,  subtract  1.  If  any  wall  is 
moist,  subtract  3. 

5.  Interior  Finish. — Ease  of  cleaning  refers  to  cleaning  of  food  cham- 
ber, all  shelves  therein,  and  the  drain  pipes.  If  ease  of  cleaning  is  ideal, 
credit  5.  If  interior  finish  is  hard  and  non-absorbent,  credit  2.  If  color 
is  white,  credit  5. 

*See  Appendix  for   tables  mentioned. 


CORKBOARD  INSULATED  REFRIGERATOR  379 

6.  Drainage. — See  that  the  trap  in  the  drain  pipe  works.  If  there  is 
proper  trapping,  credit  2.     If  there  is  proper  tubing,  credit  1. 

7.  Exterior  Finish. — If  exterior,  including  doors,  has  soHd  surface, 
easily  cleaned,  credit  1.  If  finish  is  durable  and  lasting,  instead  of  easily 
flaked  or  chipped,  credit  2.  If  hardware  is  simply  constructed,  durable 
and  easily  handled,  credit  2. 

John  R.  Williams,  M.D.,  carried  on  considerable  research 
into  refrigeration  in  the  home  to  obtain  data  for  a  paper  to 
be  presented  before  the  Third  International  Congress  of  Re- 
frigerating Industries.  Dr.  Williams  obtained  considerable 
interesting  information  in  reference  to  the  construction  and 
performance  of  household  refrigerators  in  actual  use,  the 
room  temperatures  under  which  they  operate,  the  box  tem- 
peratures at  which  food  is  stored,  the  relative  amounts  of  ice 
used,  and  so  forth.  He  points  out  most  emphatically  that 
the  weakness  of  most  "ice  boxes"  is  in  poor  insulation,  having 
found  that  very  few  refrigerators  in  common  use  have  an 
efficiency  above  25  per  cent.    He  says : 

Indeed  the  low  priced  boxes  used  in  the  homes  of  working  people  are 
probably  less  than  15  per  cent,  efficient.  This  means  that  of  100  pounds 
of  ice  put  into  a  refrigerator,  at  least  80  pounds  were  used  in  neutralizing 
the  heat  which  percolates  through  the  walls.  It  is  worthy  of  note  that  the 
market  is  flooded  with  these  shoddy  ice  boxes.  No  less  than  75  different 
makes  were  found  among  the  243  examined. 

The  U.  S.  Bureau  of  Standards,  the  New  York  Tribune 
Institute,  the  University  of  Illinois,  the  Good  Housekeeping 
Institute,  the  National  Electric  Light  Association,  the  Armour 
Institute  of  Technology,  the  Geo.  B.  Bright  Engineering  Lab- 
.oratory,  and  probably  many  others,  have  performed  interesting 
and  valuable  tests  on  ice  and  mechanically  cooled  refrigera- 
tors. The  methods  of  testing  have  varied  so  widely,  how- 
ever, that  the  results  of  one  laboratory  are  not  safely  com- 
parable with  the  results  of  another;  and  it  is  in  the  direction 
of  standardization  of  method  of  testing,  so  as  to  make  the 
results  of  all  properly  conducted  tests  readily  and  safely 
available  for  comparison,  that  attention  should  be  given. 


380  CORK  INSULATION  j 

Household  refrigerators,   as  at  present  produced,   may  be    1 
dhided  into  three  main  classes: 

(a)  Ice  cooled.  ' 

(b)  Ice  or  mechanically  cooled.  { 

(c)  Mechanically  cooled.  i 

I 
It  is  not,  in  general,  satisfactory  to  design  and  build  refriger- 
ators for  dual  service;  that  is,  a  refrigerator  correctly  designed 
for  mechanical  cooling  may  possibly  be  adjusted  to  ice,  but 
the    average   ice   refrigerator,    though    satisfactory    with    ice, 
usually  is  not  satisfactory  when  mechanically  cooled,  for  rea-   j 
sons  having  to  do  with  temperature  and  insulation,  as  elabo-   j 
rated  throughout  this  Chapter,  and  for  still  other  reasons  to  be   ! 
noted.     Tlie  ice  cooled  refrigerator,  on  the  one  hand,  aims  to   : 
fulfill  one  major  function:  j 

1.  To  maintain  at  a  suitable  and  reasonably   uniform   temperature  a    ! 
compartment  for  the  storing  of  ]ierishable  foodstufifs.  i 

The  mechanically  cooled  refrigerator,  on  the  other  hand,  must  ; 

fulfill  an  additional  major  function:  I 

2.  To  supply  at  all  times  cul)e-ico  lor  table  use.  1 
These  functions  are  sufiiciently  unrelated,  or  require  sufficient  j 
correlation,  as  to  make  the  two  types  of  refrigerators  some-  ; 
what  dissimilar  in  design.  Consequentl}',  for  the  present,  all  j 
tests  on  household  refrigeratt)rs  should  be  made  from  the 
standpoint  of  either  ice  cooling  or  mechanical  cooling. 

Considering  first  the  ice  cooled  refrigerator,  it  is  well 
understood  that  a  "suitable"  temperature  must  of  necessity 
fall  within  a  higher  zone  than  would  be  possible  with  mechan- 
ical refrigeration,  which  higher  zone  of  temperatures  has  both 
its  advantages  and  its  disadvantages.  It  imposes  a  narrow 
limit  of  safet}'  for  temperature  fluctuations  from  the  zone  of 
satisfactory  temperature  operation;  ])ut  it  provides  a  tem- 
perature zone  in  which  miscellaneous  "moist  foods"  may  be 
stored  in  the  same  compartment  with  the  minimum  loss  of  weight 
and  natural  flavor,  and,  because  of  the  air  purifying  process 
constantly  carried  on  by  the  absorption  of  odors  by  the  water 
of  ice  meltage,  it  guarantees  against  the  tainting  of  one  food 
from  the  odors  of  another. 

The  temperature  of  melting  ice  being  Z2°  F.,  the  coldest 
air  dropping  into  the  t'ood  compartment  will  range  from  about 


CORKBOARD  INSULATED  REFRIGERATOR  381 

40°  to  50°  F.,  depending  on  the  amount  of  ice  in  the  ice 
chamber,  the  rate  of  air  circulation,  the  room  temperature  and 
humidity,  and  the  insuhition  of  the  refrigerator.  The  rise  in 
temperature  of  the  air  in  passing  through  the  food  compart- 
ment may  range  front  10  to  20  degrees,  circulation,  room 
temperature  and  insulation  being  the  determining  factors. 
United  States  Government  tests*  on  a  number  of  standard 
refrigerators  show  that  the  comparative  rate  of  air  flow  in 
nine  different  refrigerators  varied  as  much  as  100  per  cent 
under  identical  operating  conditions.  A  wide  range  of  tem- 
perature between  the  coldest  and  the  warmest  points  in  the 
food  compartment  indicates  sluggish  air  circulation,  if  ice 
supply  is  adequate,  not  active  air  circulation.  The  \'ariation 
in  the  food  comj)artment  temperature  of  an  ice  refrigerator 
should  not  l)e  more  than  about  10  degrees ;  because  since  40° 
F.  is  about  the  lowest  temperature  to  be  reasonably  expected, 
50°  F.  would  then  be  the  highest  temperature,  and  50°  F.  is 
near  the  temperature  limit  at  which  many  perishable  food- 
stuffs can  be  safely  preserved. 

The  refrigerator  using  ice  may  be  expected  to  have  an 
average  temperature  in  the  food  compartment  from  20,  or  25. 
to  35  degrees  lower  than  the  room  temperature,  but  only  the 
better  types  of  refrigerators  will  ap])r()ach  the  35  degree  tem- 
perature difference  with  a  good  su])ply  of  ice  in  the  ice  com- 
partment and  the  room  temperature  at  about  90°  F.  The 
average  temperature  of  the  food  compartment  of  the  better  re- 
frigerators under  such  conditions  would  then  be  about  55°  F., 
and  in  the  poorly  constructed  ones  the  average  temperaHu'e 
would  be  65°  F.  or  more. 

The  average  temperature  of  the  food  compartment  of  an 
ice  cooled  refrigerator  ma}'  be  reduced  in  three  ways : 

1.  By  breaking  u]i  the  ice  in  the  ice  compartment  so  as  to  expose  more 
surface  to  the  circulating  air. 

2.  By  increasing  the  air  circulation. 

3.  By  increasing  the  insulation  in  the  walls  of  the  refrigerator. 

If  the  ice  is  broken  up  to  expose  more  surface  to  be  melted 
and  thus  cause  more  heat  to  l^e  absorbed  from  the  circulating 
air  of  the  refrigerator,  a  lower  temperature  will  be  produced 

*U.    S.    Bureau    of   Standards    Circular   No.    55. 


382  CORK  INSULATION 

at  the  daily  expense  of  labor  and  ice ;  and  some  improvement   I 
may  be  effected  by  the   manufacturer  through  a  change  in   { 
the  interior  design  of  the  refrigerator  that  will  locate  the  ice 
compartment   in  a   top-center   position,   and   at  no  additional 
expense;  but  by  increasing  the  thickness   of  permanently   effi-  j 
cient  insulation  in  the  walls  of  the  refrigerator,  at  a  low  per-  > 
centage  of  increase  in  manufacturing  cost,  the  food  compart- 
ment may  be  so  effectively  isolated  from  outside  heat  influ- 
ences as  to  make  the  maintenance  of  correct  temperatures  by 
the  melting  of  ice  a  practical  matter  even  on  the  hottest  and 
the  most  humid  days  of  the  year.     Experience  has  safely  fixed 
this  insulation  at  three  inches  of  pure  corkboard,  when  prop- 
erly incorporated  in  the  construction  of  the  refrigerator. 

From  these  few  observations,  it  would  appear  to  be  of  but 
limited  value  to  test  poorly  designed  and  badly  constructed 
refrigerators  that  are  to  be  cooled  with  ice.  Consequently, 
the  first  point  to  cover  in  planning  for  a  test  of  an  ice  refrig- 
erator should  be  a  careful  investigation  into  the  design  and 
construction  of  the  unit;  and  if  this  research  reveals  a  lack 
of  reasonable  consideration  for  basic  principles  of  design  and 
construction,  as  they  are  then  generally  known  and  under- 
stood, there  probably  will  be  good  reason  to  abandon  the 
intention  to  perform  the  test.  Otherwise,  the  following  test 
conditions  should  be  observed : 

(a)  Refrigerators  of  identical  shape  and  size  must  be  selected  for 
comparative  test  purposes.  It  is  suggested  that  standard  sizes  be  deter- 
mined upon  for  a  top-icer  apartment  refrigerator,  a  side-icer  small  resi- 
dence refrigerator  and  a  center-icer  large  residence  refrigerator,  and  that 
all  future  tests  be  run  on  refrigerators  as  near  those  sizes  as  possible. 

(b)  A  constant  temperature  room  should  be  used,  the  temperature 
held  uniform  to  within  one  degree  Fahr.  by  electric  heater  placed  within 
hollow  walls  of  the  test  room  and  controlled  by  thermostat.  A  room  tem- 
perature of  at  least  85°  F.  is  suggested  for  test  purposes. 

(c)  Control  of  the  humidity  of  the  constant  temperature  room  should 
be  effected  by  suitable  means,  tests  having  demonstrated  that  a  consider- 
able increase  in  the  percentage  of  ice  melting  is  effected  by  increasing  the 
percentage  of  relative  humidity  in  a  constant  temperature  room  from  a  low 
to  a  high  point. 

(d)  The  ice  should  be  carefully  regulated  on  the  basis  of  weight,  and 
of  one  piece,  of  size  or  shape  suitable  for  the  ice  compartment  of  the 
class  of  unit  tested. 

(e)  The  ice  should  be  only  hard,  "black"  ice. 


CORKBOARD  INSULATED  REFRIGERATOR 


383 


(f)  The  ice  should  be  prepared  outside  the  test  room,  and  placed  in 
the  refrigerator  during  a  fixed  period,  at  the  same  hour,  every  day  (24- 
hour  icing),  old  ice  to  be  removed  and  weighed  simultaneously. 

(g)  The  food  compartment  of  the  refrigerator  should  be  empty,  it 
being  known  that  over  90  per  cent,  of  refrigerator  losses  are  caused  by 
the  heat  leakage  through  the  walls  of  the  refrigerator,  and  less  than  10 
per  cent,  in  cooling  food  and  opening  doors,  under  normal  household 
operation. 

(h)  Record  of  refrigerator  temperatures  should  be  made  every  hour, 
by  suitable  means,  such  record  to  be  taken  at  three  designated  points  in 


^ 

^-           - — , 

1 

1 

I 

<:r^ 

THERMOST>Or              6WITCH  AND 

1 

f 

1 

FOSES  FOR  HEATERS 

ACBtSTOS  — 
LINED 

ELECTRIC- 
HEATERS 

RlMOVABLt 

RCFRIQeRAToa 

ooot<  -^ 

r          ^ 

-^      — 

181.— CONSTANT    TEMPERATURE    TESTING    ROOM— HOLLOW 
WALL    TYPE. 


the  food  compartment  of  the  apartment  refrigerator,  at  four  points  in  the 
small  residence  refrigerator  and  at  five  points  in  the  large  residence 
refrigerator. 

(i)  Record  of  the  relative  humidity  of  the  food  compartment  should 
be  made  simultaneous  with  temperatures,  by  suitable  means. 

(j)  Drip  water  should  be  weighed  every  hour,  and  the  record  used  as 
a  check  on  the  actual  weight  of  ice  melted  during  the  test. 

(k)  Three  days  preliminary  operation  should  be  allowed  to  establish 
a  temperature  equilibrium  in  the  walls  of  the  refrigerator  before  the  test 
proper  should  be  started,  and  the  test  should  then  continue  for  30  more 
days. 

Tests  performed  under  standardized  conditions,  values  for 
such    standards   to   be    fixed    upon   a   practical   basis   for   test 


384  CORK  INSULATION 

purposes  and  a  basis  most  nearly  conforming  to  the  practices 
of  the  ice  industry  as  regards  service  to  the  household,  should 
be  comparable,  as  to  ice  consumption,  food  compartment 
temperatures  and  humidity.  And  if  to  such  test  results  is 
appended  a  record  of  the  exact  condition  of  the  refrigerator 
wall  construction,  as  to  moisture,  observed  immediately  after 
the  conclusion  of  the  30-day  test  by  cutting  all  the  way 
through  the  wall  construction  to  the  interior  lining,  the  ability 
of  the  refrigerator  to  maintain  its  efficiency  will  be  more  easily 
predicted. 

Considering  next  the  mechanically  cooled  refrigerator,  the 
operation  of  the  apparatus  is  intended  to  be  automatic  but 
conditions  arise  at  times  that  make  the  simultaneous  carrying 
on  of  its  two  major  functions,  previously  mentioned,  almost 
impossible.  In  designing  the  automatic  control,  a  compromise 
is  therefiore  effected  in  order  to  obtain  the  best  all  'round  per- 
formance possible. 

By  pressure  or  thermostatic  control,  the  temperature  of 
the  cooling  element  is  held  at  a  more  or  less  constant  tem- 
perature at  all  times,  because  of  the  necessity  of  producing 
cube  ice,  instead  of  the  machine  being  automatically  controlled 
directly  by  the  temperature  of  the  food  compartment. 

It  is  thus  apparent  that  the  commonly  used  method  of 
control  is  not  capable,  without  readjustment,  of  maintaining 
a  constant  temperature  in  the  food  space  under  wide  varia- 
tions in  room  temperatures,  such  as  are  occasioned  by  the 
hour  of  the  day  or  the  season  of  the  year.  In  general,  there 
may  reasonably  be  expected  a  three  degree  change  in  refrig- 
erator temperature  for  each  ten  degrees  alteration  of  room 
temperature,  which  will  give  some  idea  of  the  probable  tem- 
perature fluctuation  in  the  food  compartment  of  a  fair  quality 
refrigerator  under  any  given  adjustment  of  automatic  control. 
If  the  unit  operates  in  a  heated  room  where  the  temperature 
is  subject  to  but  slight  variation  day  or  night,  winter  or  sum- 
mer, its  regulation  is  likely  to  be  fairly  good,  without  making 
seasonal  adjustments  of  the  regulating  device ;  but  under 
conditions  not  approaching  such  an  ideal,  foods  are  likely  to 
be  either  frozen  or  insufficiently  cooled. 


CORKBOARD  INSULATED  REFRIGERATOR  385 

These  obserxations  are  based  on  a  refri^^erator  cabinet 
of  fair  quality,  as  respects  insulation;  but  as  the  permanent 
insulating  qualities  of  mechanically  cooled  household  refrig- 
erators are  improved,  so  the  difiticulties  of  food  compartment 
temperature  control  are  reduced.  The  well  insulated  unit, 
such  as  a  cabinet  containing  three  inches  of  pure  corkboard  set 
tightly  against  the  interior  lining  at  all  points,  is  not  sensitive 
to  room  temperature  fluctuations  to  any  appreciable  degree, 
and  consequently  may  easily  perform  its  two  major  functions 
with  that  degree  of  accurac}-  required  by  a  discriminating 
owner.  At  the  same  time,  such  a  mechanical  unit  can  be 
operated  at  a  cost  that  will  be  low  enough  to  justifv  the 
extra  investment. 

In  testing  mechanical  units,  the  same  test  conditions 
should  be  observed  as  outlined  for  ice  refrigerators,  with  but 
a  few  changes.  The  kiloAvatt-hours  power  consumption  is 
measured  instead  of  ice  melted.  A  gi\en  quantity  by  weight 
of  water  at  say  70°  F.  temperature  is  filled  into  standard  cube 
trays  that  have  been  cooled  to  the  same  temperature,  and  the 
trays  are  placed  in  the  refrigerator  once  e\'ery  day  for  the 
cubes  to  be  frozen,  the  frozen  cubes  from  the  day  before  being 
simultaneously  removed.  If  it  is  desired  to  put  a  normal 
"food  load"  on  either  the  ice  cooled  or  the  mechanically  cooled 
refrigerators,  same  should  amount  to  8  B.t.u.  per  hour,  per 
cubic  foot  of  cabinet  contents,  same  being  introduced  electric- 
ally by  an  immersion  heater  in  a  container  of  oil  placed  at  a 
given  point  in  the  food  compartment. 

On  account  of  the  lower  temperatures  in  general  desired 
by  owmers  and  maintained  in  mechanical  units,  especial 
attention  must  be  paid  to  the  subject  of  condensed  moisture 
within  the  wall  construction  of  the  mechanically  cooled  cabinet 
at  the  end  of  the  30-day  test  period. 


CHAPTER  XVII. 

DEVELOPMENT  OF  THE  CORKBOARD  INSULATED 
ICE  CREAM  CABINET. 

158. — Growth  of  the  Ice  Cream  Industry. — Ancient  records 
reveal  that  Saladin,  Sultan  of  Egypt  and  Syria,  sent  Richard  I, 
King  of  England,  a  frozen  sherbet  in  the  12th  century;  that 
Marco  Polo,  the  great  Italian  navigator,  brought  recipes  for 
water  and  milk  ices  from  Japan  and  China  in  the  13th  century; 
and  that  Catherine  d'Medici  when  leaving  Florence,  Italy,  for 
France,  in  the  16th  century,  took  with  her  certain  chefs  skilled 
in  the  preparation  of  frozen  creams  and  ices. 

Frozen  desserts  were,  however,  regarded  as  luxuries,  to 
be  indulged  in  only  upon  occasion,  until  comparatively  recent 
times.  In  the  United  States,  ice  cream  became  popular  as  a 
table  dessert  among  the  colonists.  The  first  public  advertise- 
ment of  ice  cream  appeared  in  The  Post  Boy,  a  New  York 
paper,  in  1786;  but  it  was  not  until  about  1851  that  an  attempt 
was  made  to  manufacture  ice  cream  in  wholesale  quantities. 
In  that  year  John  Fussell,  a  milk  dealer  in  Baltimore,  Mary- 
land, became  interested  in  ice  cream  in  an  effort  to  find  a 
profitable  outlet  for  surplus  sweet  cream  that  he  had  on  hand 
from  time  to  time.  The  manufacture  of  ice  cream  was  under- 
taken as  a  side  line,  and  sold  at  wholesale,  but  the  business 
proved  so  profitable  that  Fussell  disposed  of  his  entire  milk 
business  and  devoted  his  whole  attention  to  the  new  industry. 
His  remarkable  success  may  be  judged  from  the  fact  that  he 
later  established  ice  cream  factories  in  Washington,  Boston 
and  New  York  City. 

Perry  Brazelton,  of  Mt.  Pleasant,  Iowa,  studied  the  whole- 
sale ice  cream  business  in  Fussell's  Washington  plant;  and 
later  established  his  own  plant  in  St.  Louis,  Missouri,  followed 
by  still  others  in  Cincinnati,  Ohio,  and  Chicago,  Illinois,  which 

386 


CORKBOARD  ICE  CREAM  CABINET 


387 


is  indicative  of  the  success  that  attended  his  efforts  in  the 
new  industry  in  the  Middle  West.  From  then  on  there  was  a 
steady  growth  in  this  branch  of  the  dairy  industry,  but  rapid 
expansion  did  not  begin  until  the  shortage  of  natural  ice  in 
1890  gave  the  art  of  ice  making  and  refrigeration  the  impetus 
necessary  to  establish  that  industry  on  a  successful  commer- 
cial basis.  Then  great  improvements  in  machinery,  and  meth- 
ods of  ice  cream  manufacture,  were  rapidly  introduced  during 


FIG.    182.— CORKBOARD   INSULATED    LONG-DISTANCE    REFRIGERATED 
ICE  CREAM  TRUCK. 

the  next  two  decades,  until  by  the  end  of  1912  there  was  a 
reported  total  output  of  154  million  gallons  of  ice  cream  valued 
at  160  million  dollars. 

The  National  Association  of  Ice  Cream  Manufacturers  was 


organized  in  1906,  to  more  effectively  promote  the  interests  of 
ice  cream  manufacturers  by  assisting  the  industry  to  develop 
along  permanent,  substantial  lines,  through  standardization  of 
factory  operations,  pure  food  laws,  and  so  forth.  Trade  asso- 
ciations and  trade  papers  did  much  to  promote  the  welfare  of 
the  industry,  by  teaching  a  common-sense  code  of  ethics  and 
by  acting  as  a  clearing  house  for  its  numerous  activities.  Many 
schools  and   colleges  took  up  the  teaching  of  the  principles 


I 


388  CORK  INSULATION 

and  practices  pertaining-  to  the  manufacture  of  ice  creams  and 
ices.  Through  the  cooperation  of  these  useful  agencies,  the 
public  was  enabled  to  receive  such  ample  protection  against 
impure  and  unsatisfactory  ice  cream  products  as  to  so  solidly 
establish  the  industry  that  by  the  end  of  1926  the  output  was 
325  million  gallons  valued  at  300  million  dollars  (wholesale). 

159. — Ice  and  Salt  Cabinets. — It  has  been  noted  that  salt- 
petre mixed  with  snow  was  used  for  cooling  licpiids  centuries 
ago  in  India,  but  the  17th  century  saw  probably  the  first  seri- 
ous attempt  to  utilize  that  method  of  refrigeration  to  produce 
ice  and  frozen  desserts.  The  low  temperature  produced  by 
mixing  ice  and  salt  is  due  of  course  to  the  fact  that  salt  lowers 
the  melting  point  of  ice  to  about  5°  F.  (-15°  C.)  and  keeps  it 
there  until  all  the  ice  is  melted  by  heat  rapidly  absorbed  from 
surrounding  objects,  which  explains  wdiy  a  can  of  freshly  made 
ice  cream  placed  in  an  insulated  cabinet  and  surrounded  with 
cracked  ice  and  salt  will  harden  by  giving  up  its  heat  to  the 
low  temperature  mixture  at  the  expense  of  melting  the  ice,  all 
as  elaborated  in  the  section  of  this  book  on  "The  Study  of 
Heat."  Since  the  ice  is  melted  by  heat  extracted  from  the  ice 
cream,  and  from  the  walls  of  the  cabinet,  which  gets  its  heat 
from  the  surrounding  atmosphere,  it  is  necessary  to  set  up  in 
those  cabinet  walls  an  efficient  barrier  against  the  infiltration 
of  heat  from  the  warm  air  of  the  room. 

The  ice  cream  industry  was  founded  upon  the  fact  of  .the 
melting  point  of  ice  being  lowered  in  the  presence  of  salt. 
A  mixture  of  ice  and  common  salt  was  the  only  refrigerant 
used  to  congeal  cream,  and  to  keep  the  frozen  mass  in  a  satis- 
factory state  of  preservation  for  palatable  consumption,  for 
many  years  before  and  after  the  advent  of  mechanical  refrig- 
eration. Low  temperature  brine  produced  by  a  mixture  of 
cracked  ice  and  salt,  or  low  temperature  brine  produced  by 
adding  salt  to  water  and  cooling  the  mixture  by  mechanical 
means,  differ,  in  so  far  as  the  manufacture,  hardening  and 
storage  of  ice  cream  in  the  plant  is  concerned,  only  in  that 
the  salt  and  ice  mixture  is  more  dif^cult  to  handle  and  its 
temperature  is  not  as  easily  controlled.  In  either  case,  about 
equally  good  manufacturing  results  were  possible,  although 
mechanical    refrigeration    in    the   plant   eft'ected   a   very   great 


CORKBOARD  ICE  CREAM  CABINET 


389 


saving  in  cost  of  production  by  placing  all  manufacturing 
operations  under  the  complete  and  accurate  control  of  rela- 
tivel}'  few  workmen. 

Outside  the  plant,  however,  on  delivery  wagons  and  trucks, 
on  railway  cars,  in  retail  cabinets  and  soda  fountains,  the 
salt  and  ice  mixture  was  depended  on  exclusively,  until  the 
last  few  years,  for  necessary  refrigeration  for  the  preserva- 
tion of  ice  cream  until  consumed.  Early  cabinets  were  built 
of  heavy  tongued  and  grooved  planks  of  wood,  with  no  insu- 


FIG.    183.— ARTIST'S    CONCEPTION    OF   THE   OLD    UNINSULATED  ICE 
CREAM   CABINET. 

lation  other  than  the  wood  itself,  just  about  as  the  early 
household  ice  chest  was  constructed;  but  cabinets  with  hollow 
walls,  filled  usually  with  sawdust,  came  into  early  use  and 
remained  a  long  time.  They  left  much  to  be  desired,  how- 
ever, because  the  low  temperature  necessary  for  the  holding 
of  ice  cream  caused  heavy  condensation  of  moisture  within 
the  air  entrapped  between  the  sawdust  particles,  and  the 
cabinet  walls  became  ice  laden  and  water-soaked.  Granu- 
lated cork  was  next  tried  as  the  loose  fill  insulating  material, 
with  better  success,  but  still  with  much  to  be  desired  both 
from  the  standpoint  of  insulating  efficiency  and  a  dry  condi- 
tion of  the  walls  of  the  cabinet. 

In   those  days   it  was  necessary,   in   summer,   for   the   ice 


390  CORK  INSULATION 

cream  manufacturer  to  service  or  ice  his  cabinets  in  retail 
stores  twice  daily.  In  an  effort  to  cut  this  expensive  service 
to  one  daily  icing,  the  Rieck  ice  cream  interests,  of  Pittsburgh, 
Pennsylvania,  undertook  experiments  w^ith  ice  cream  cabinets 
insulated  with  sheets  of  pure  corkboard,  an  insulation  specifi- 
cation for  retail  ice  cream  cabinets  almost  unheard  of  up  to 
that  time  (about  1912),  and  an  extravagance  thought  to  be 
wholly   unjustified.     The    experiments    started    with    cabinets 


FIG.  184.— MODERN'  CORK  INSULATED  ICE  CREAM  SHIPPING  CONTAIN- 
ER;  REPLACES   ICE  PACKED   TUB. 

containing  one  inch  thick  corkboard,  which  thickness  was  then 
increased  little  by  little  until  satisfactory  results  were  obtained, 
in  conjunction  with  the  use  of  a  suitable  ice  and  salt  mixture. 
The  results  of  these  experiments  did  much  to  establish  pure 
corkboard  as  the  standard  insulation  for  retail  ice  cream 
cabinets,  and  it  has  so  remained,  the  only  improvement  being 
in  the  methods  followed  in  putting  the  corkboard  in  place  and 
in  an  economical  distribution  throughout  the  cabinet  of  the 
thickness  of  corkboard  used.  In  general,  the  details  of  cab- 
inet assembly,  with  respect  to  insulation,  should  be  predicated 
on  a  thorough  understanding  of  the  basic  principles  pertain- 


CORKBOARD  ICE  CREAM  CABINET  391 

ing  to  the  insulation  of  walls  and  structures  to  be  subjected 
to  low  temperatures,  as  previously  elaborated  in  this  text, 
to  the  end  that  ice  cream  cabinets  may  contain  adequate  insu- 
lation installed  so  as  to  insure  permanent  cabinet  efficiency. 

160. — Mechanical  Ice  Cream  Cabinets. — The  trend  in  the 
development  and  applications  of  mechanical  refrigerating-  ma- 
chinery was  slowly  but  constantly  from  large  many-ton  plants 
toward  smaller  units,  much  as  in  the  development  of  electric 
power  the  large-motor  main-shaft  drive  gave  way  a  little  at 
a  time  to  individual  drive  by  small  motors.  But  the  high 
pressures  at  which  ammonia  compression  refrigerating  ma- 
chines operate,  placed  restrictions  on  the  smallness,  the  light- 
ness, and  the  cost  of  production  of  the  ammonia  units  of 
fractional-ton  capacity,  past  which  it  was  not  practical  for 
the  manufacturer  to  go.  And  that  minimum  cost  was  too 
high  for  general  application  to  small  refrigeration  duty,  such 
as  the  cooling  of  household  refrigerators  and  retail  ice  cream 
cabinets,  when  in  competition  with  ice,  and  ice  and  salt 
mixtures. 

The  use  of  a  refrigerant  that  could  be  effectively  operated 
at  relatively  low  pressures,  such  as  sulphur  dioxide,  proved 
to  be  the  solution  of  the  problem,  which  development  estab- 
lished the  small  fractional-ton  refrigerating  machine  as  a 
practical  and  economical  refrigerating  unit  through  much 
lighter  and  simpler  construction  and  greatly  reduced  cost. 
However,  in  the  practical  application  of  such  household  re- 
frigerating units,  as  they  quickly  came  to  be  known,  it  was 
determined  that  their  successful  operation,  as  well  as  their 
low  manufacturing  cost,  depended  on  a  certain  restriction  of 
the  unit  refrigerating  capacity. 

Thus  the  efforts  to  reduce  the  cost  of  production  of  the 
fractional-ton  ammonia  compression  machine  to  the  point  of 
successful  competition  with  ice  and  salt  mixtures  were,  m 
general,  unsuccessful;  while  the  efforts  to  economically  raise 
the  unit  refrigerating  capacity  of  the  sulphur  dioxide  type  of 
machine  enough  to  handle  the  heavier  duty  cabinets  were,  in 
general,  unavailing.  But  virtually  by  the  simple  expedient 
of  increasing  the  thickness  of  the  corkboard  insulation  in  ice 
cream  cabinets  to  be  mechanically  cooled,  and  by  so  setting 


392  CORK  INSULATION 

the  insulation  in  the  walls  of  the  cabinet  as  to  guarantee  the 
permanent  thermal  efficiency  of  the  cabinet,  the  small  low 
pressure  carbon  dioxide  type  of  machine  was  adapted  to  retail 
ice  cream  cabinet  refrigeration  loads,  and  took  the  field  from 
the  fractional-ton  high  pressure  ammonia  machine. 

These  considerations  are  briefly  set  forth  here,  emphasized 
in  their  relation  to  insulation,  merely  to  show  the  part  cork- 
board  played  in  the  preliminary  research  and  engineering 
development  work  incident  to  the  beginnings  of  what  is  now 
a  large  industry — the  mechanical  ice  cream  cabinet  industry, 
which  the  Crouse-Tremaine  interests,  of  Detroit,  Michigan, 
are  given  considerable  credit  for  having  pioneered. 

161. — Typical  Details  of  Ice  Cream  Cabinet  Construction. 
— It  would  serve  little  purpose  to  illustrate  in  this  book  all 
the  different  makes  and  types  of  ice  cream  cabinets — ice  and 
salt  cabinets  and  mechanical  cabinets — manufactured  in  the 
United  States,  and  for  that  reason  but  a  very  few  of  them, 
selected  at  random,  are  shown  and  described*  in  this  Article : 

BROOKS  NEW  DOUBLE  ROW  TWO-TEMPERATURE 
DRYPAK  CABINET. 

Frame. — Built  of  2  x  2  long  leaf  heart  pine  lumber,  possessing  great 
tensile  strength  and  durability,  without  excessive  weight.  This  material 
contains  a  large  amount  of  turpentine  and  rosin  that  prevents  decay. 

The  Bottoms. — Made  of  1-inch  gulf  cypress  are  strong  and  securely 
fastened  to  the  frame,  reinforced  with  skids  made  of  long  leaf  heart  pine. 
The  bottoms  of  the  Brooks  Drypak  Cabinets  are  made  to  hold  their  weight. 
They  can  never  sag  or  be  pushed  out. 

Pure  Corkboard  Insulation.— The  insulation  is  extra  heavy  pure  cork- 
board,  consisting  of  6  inches  in  the  bottom  and  4  inches  in  the  sides  and 
ends.  We  do  not  attempt  to  save  cork  by  tapering  the  insulation  in  the 
side  walls,  as  it  is  just  as  necessary  to  keep  the  heat  out  at  the  top  of  the 
side  walls  as  it  is  at  the  bottom  of  the  side  walls.  We  therefore  use  4 
inches  of  pure  corkboard  in  the  sides  and  ends  all  of  the  way  up  to  the 
top  of  the  cabinet. 

Hermetically  Sealed. — Besides  the  precaution  taken  to  have  all  joints 
lapped,  or  perfectly  butted,  the  entire  corkboard  insulation  is  sealed  by 
flowing  on  a  thick  layer  of  hot  asphaltum.  This  assures  the  filling  and 
closing  up  of  all  pores,  joints  and  cracks,  which  prevents  the  leakage  of 
refrigeration  or  the  penetration  of  heat. 


•Descriptions  are  those  of  the  manufacturer,  and  are  to  be  accepted  only  for  what 
they  may  prove  to  be  worth. 


CORKBOARD  ICE  CREAM  CABINET  393 

A^7  Substifutcs  for  Corkboard. — There  are  no  substitutes  for  cork- 
board  used  in  any  part  of  these  cabinets.  The  insulation  will  remain  in 
l)lace  and  retain  its  efficiency  during  the  entire  life  of  the  cabinet.  Buy 
plenty  of  insulation  once  and  save  icing  expenses  daily.  There  is  no 
better  investment  for  ice  cream  manufacturers  than  plenty  of  pure  cork- 
board  insulation  in  ice  cream  cabinets.  It  pays  big  dividends  every  day 
the  cabinets  are  in  use. 

Tlic  Corners. — Nickel  zinc  angles  protect  the  corners  and  add  a 
pleasing  appearance  to  these  cal)inets.  They  are  fastened  with  brass  nails 
and  will  not  rust  or  corrode. 

Tops. — The  tops  are  made  from  heavy,  straight  grain  gulf  cypress 
lumber,   the   corners   are   rigidly   secured   and   the   construction  throughout 


1-IG.    185.— BROOKS   COliKBOARD   INSULATED   DRVPAK   ICE   CREAM 
CABINET. 

strong  and  substantial.  These  tops  are  arranged  to  make  filling  easy, 
without  undue  loss  of  time  or  refrigeration. 

The  Lids. — The  lids  are  large  enough  to  remove  empty  cans  and 
replace  them  with  full  cans  of  cream  without  removing  the  top  of  the 
cabinet  and  exposing  other  compartments.  The  lids  are  also  insulated 
with  pure  corkboard.  A  "hand  grip"  is  carved  into  the  one-piece  cover, 
so  that  there  are  no  metal  handles  to  break  off  or  rust,  no  knobs  to 
obstruct  an  even  surface.  The  edges  are  designed  to  seal  against  loss  of 
refrigeration  and  yet  make  opening  and  closing  easy. 

The  I'iiiish. — .Solid,  laminated,  three-ply,  waterproof  panels,  selected 
for  graining  and  durability,  arc  used  on  all  sides  and  ends.  The  finish  is 
rich  old  mahogany,  four-coat  work,  giving  a  smooth,  hard  surface  that 
resists  wear. 

Sheet  Metal  //'or/.'.— The  linings  and  cans  are  made  from  genuine 
Armco    Ingot    iron.     This    well-known    l)rand    of    copper-bearing    metal, 


394 


CORK  INSULATION 


heavily  galvanized,  is  further  assurance  of  the  definite  and  dependable 
values  built  into  Brooks  Drypak  Cabinets. 

Ice  Compartments. — The  Brooks  Drypak  Cabinet  ice  compartments  are 
large  enough  to  provide  ample  capacity  to  care  for  exceptional  conditions 
during  the  summer  months.  These  cabinets  will  keep  cream  in  perfect 
condition  for  forty-eight  hours  or  more. 

Drains. — One-piece,  leak-proof  and  non-corrosive  Smith  and  Mann 
valves  are  used.  They  are  of  ample  size  to  perfect  quick  drainage  and 
are  threaded  for  three-quarter  inch  hose  connection. 

Mounted  on  Skids. — For  a  sanitary  base  and  to  facilitate  moving, 
Brooks  Drypak  Cabinets  are  mounted  on  sturdy  skids ;  there  arc  no  legs 
to  break  oflF. 

Workmanship. — The  workmanship  throughout  the  cabinets  is  first 
class  in  every  particular.  The  design  is  the  result  of  long  experience 
with  the  problems  of  ice  cream  manufacturers,  by  the  men  who  actually 
manufacture  Brooks  Drypak  Cabinets. 

Manufactured  by  Brooks  Cabinet  Co.,  Norfolk,  Virginia. 


FIG.   186.— SECTION   OF  NELSON   DUPLEX-ZERO  DRY-PACK  CABINET. 


NELSON  DUPLEX-ZERO  DRY-PACK  CABINETS. 

Insulation. — A  cabinet   can  be   no   more   efficient   than   its   insulation. 
The  high  efificiency  of  Duplex-Zero  cabinets  is  guaranteed  by  the  perfect 


CORKBOARD  ICE  CREAM  CABINET  395 

design  and  the  massive  insulation  of  solid  slabs  of  sheet  cork,  tapering 
from  3  inches  on  sides  and  ends  at  the  top  to  5  inches  at  and  on 
bottom,  heat  treated  with  a  special  asphaltum  base  formed  into  a  solid, 
continuous,  air-tight,  moisture-proof  and  settle-proof  wall  around  and 
under  the  ice  chamber.  This  construction  insures  maximum  refrigerating 
results — 48  to  72  hours  on  one  icing. 

Lining. — The  metal  lining  is  of  22-gauge  copper  bearing  iron,  heavily 
galvanized,  fitting  snugly  against  the  corkboard,  giving  maximum  wear,  yet 
easily  removed  and  replaced. 

Finish. — Added  insulation  and  durability  are  assured  by  the  use  of 
California  redwood  on  all  Nelson  cabinets. 

Corners. — Duplex-Zero  Dry-Pack  cabinets  are  equipped  with  bright  metal 
corner  irons. 

Dram.^Drains  quickly  with  Nelson  patented  brass  drain. 
Manufactured  by  C.  Nelson  Manufacturing  Co.,  St.  Louis,  Missouri. 


FIG.     1S7.— SECTION    OF    GRAND    RAPIDS    CABINET    CO.    TRAY-PACK    ICE 
CREAM  CABINET.   (PATENTED  JAN.  25,   1926.) 

GRAND  RAPIDS  CABINET  CO.  "TRAY-PACK"  ICE  CREAM 
CABINETS. 

Description.—Tht  accompanying  figure  shows  the  position  of  the 
trays,  the  abundance  of  scientifically  distributed  corkboard  insulation,  and 
the  individual  servicing  covers  for  each  side  of  cabinet.  These  covers 
permit  servicing  without  exposing  ice  cream — a  dccidely  worthwhile  sani- 
tary feature. 

Operaton. — The  "Tray-Pack"  service  method  simply  consists  of  the 
removal  of  the  trays  by  the  service  man  from  the  Tray-Pack  cabinet,  the 


396 


CORK  INSULATION 


dumping  of  the  brine  at  the  curb  or  other  suitable  place,  the  repacking  of 
Ihe  trays  at  the  truck,  and  the  replacement  of  the  trays  in  the  Tray-Pack 
cabinet.  That's  all.  No  drip,  no  dirt,  no  muss  in  the  dealer's  store.  Just 
a  few  minutes'  work,  and  all  is  set  for  two  days  or  more  of  perfect 
refrigeration. 

Sizes. — Made  in  standard  2-,  3-,  4-,  5-,  and  6-hole  "Tray-Pack"  sizes. 
Finish  is  rich  walnut  color.  Also,  obtainable  with  two  separate  compart- 
ments, suitable  for:  (1)  two  temperatures  for  ice  cream;  (2)  one  com 
partmcnt  shut  off  during  dull  season;  (3)  one  compartment  for  milk  or 
bottled  goods. 

Insulation. — Only  the  best  insulation  obtainable  is  used  in  "Tray- 
Pack"  ice  cream  cabinets — pure  compressed  corkboard,  it  being  more  imper- 
vious 1o  water  than  any  other  known  insulating  material.  Asphaltum  and 
other  products  are  applied  hot  on  both  sides  of  the  corkboard  as  assem- 
bled in  the  cabinet,  so  as  to  exclude  all  air  from  between  the  insulation 
and  the  inner  cabinet  tank  and  from  between  all  joints  in  the  corkboard 
sheets  and  thus  exclude  all  condensed  water  from  the  insulation'  and  obvi- 
ate destruction  of  the  insulation  by  the  expansion  of  freezing. 

Manufactured  by  Grand  Ra])ids  Cabinet  Co.,  Grand  Rapids,  Michigan. 


nT'^"" 


188.— SECTIONAL  VIEW  OF  NIZER  SELF-CO .\T.\IXED  \V.\TER  COOLED 
ELECTRIC  ICE  CREAM   CARIXKT. 


NIZER   WATER-COOLED    SELF-CONTAINED    ELECTRIC 
ICE  CREAM  CABINET. 

General. — The  figure  shows  a  sectional  photograph  of  one  of  ibe  many 
Nizer  ice  cream  cabinets,  which  illustrates  particularly  the  corkboard 
insulation. 


I 


CORKBOARD  ICE  CREAM  CABINET 


397 


Insulation. — There  are  3  inches  of  pure  compressed  corkboard  on 
the  bottom,  2  inches  on  the  sides  and  1  inch  on  top.  The  insulation  is 
not  composed  of  single  thicknesses  of  corkboard,  but,  with  the  exception  of 
the  top,  of  two  thicknesses,  separated  by  sheets  of  heavy  waterproof  paper. 
There  are  also  several  sheets  of  this  paper  between  the  insulation  and  the 
brine  tank,  as  well  as  on  the  outside  surface  of  the  insulation.  Such 
places  as  cannot  be  efifectively  sealed  with  corkboard  (around  the  gas  line 
for  example)  are  packed  tightly  with  cork  plastic  insulation. 

Assembly. — The  method  of  assembly  of  the  insulation  in  the  cabinet, 
consists  in  using  sheets  of  cork  made  slightly  oversize  and  pressed  firmly 
into  position,  thus  making  perfectly  tight  joints  without  the  use  of  sealing 
material.  All  joints  in  one  layer  of  corkboard  are  staggered  with  respect 
to  the  joints  in  the  other  layer,  so  as  to  further  prevent  the  passage  of 
heat. 

]\Ianufacture<!  liy  Kelvinator,  Inc.,  Xizer  Division,  Detroit,  Michigan. 


FIG.    189.— UXIVRSAL   COOLER  CORP.   ELECTRICALLY   REFRIGERATED  ICE 
CREAM  CABINET. 

UNIVERSAL  COOLER  CORPORATION  ELECTRICALLY 
REFRIGERATED  ICE  CREAM  CABINET. 

Requirements. — In  undertaking  to  supply  the  trade  with  an  acceptable 
electrically  refrigerated  ice  cream  cabinet,  there  were  two  problems  which 
presented  themselves.  The  first  had  to  do  with  creating  a  machine  for 
producing  a  low  temperature  within  the  cabinet  of  such  a  degree  as  would 
keep  the  ice  cream  in  the  best  possible  condition,  and  the  second  having  to 
do  with  the  maintenance  of  this  temperature. 


398 


CORK  INSULATION 


The  Machine. — The  Universal  Cooler  Corporation  were  readily  able  to 
satisfy  this  first  requirement,  with  a  unit  that  was  both  simple,  compact 
and  economical,  and  could  produce  the  low  temperature  required. 

The  Cabinet. — The  second  problem  which  attached  to  the  maintenance 
of  this  low  temperature  was  one  which  depended  entirely  upon  the  con- 
struction of  the  cabinet. 

Low  Power  Cost. — If  the  cabinet  was  properly  built  and  correctly 
msulated,  it  meant  that  the  mechanical  cooling  unit  was  only  called  upon 
to  operate  for  the  shortest  possible  time,  with  a  consequent  low  current 
consumption,  and,  of  course,  a  longer  life  for  the  machine. 

The  Insulation. — Therefore,  they  undertook  to  devise  a  cabinet  which 
employed  corkboard  as  the  insulating  material.  The  cork  employed  in 
the  ice  cream  cabinet  adopted  by  the  Universal  Cooler  Corporation  is  in 
solid  slabs,  which  lap  at  corners,  top  and  bottom,  and  are  treated  with  a 
hot  asphaltum  base  product  known  as  "Hydrolene,"  so  that  the  interior 
of  the  box  is  a  solid,  continuous,  air-tight,  moisture-proof,  and  settle- 
proof  wall  around  and  under  the  ice  chamber. 

Corkboard. — The  necessity  for  having  the  cork  in  continuous  slabs 
is  for  the  purpose  of  eliminating  cracks  and  voids  which  would  permit 
ordinary  atmospheric  humidity  to  creep  in,  become  solidified  when  the 
cabinet  is  in  operation  and  thus  dissipate  some  of  the  effectiveness  of  the 
box,  and  when  the  cabinet  is  not  in  use  this  moisture  would  melt,  run  down 
into  the  bottom  of  the  box,  become  stagnant,  and  cause  unpleasant  odors. 

Manufactured  by  the  Universal  Cooler  Corporation,  18th  and  Howard 
streets,  Detroit,  Michigan. 


FIG.    190.— SERVEL    8-IIOLE,    DOUBLE    ROW,    TWO    TEMPERATURE    ELEC- 
TRICAL    ICE    CREAM    CABINET. 

SERVEL  ALL-STEEL  ICE  CREAM  CABINETS. 

Insulation. — The   Servel  line  of  ice  cream  cabinets   is  considered  the 
best  insulated  cabinet  on  the  market.     For  the  single  row,  two  layers  of 


I 


CORKBOARD  ICE  CREAM  CABINET 


399 


3-inch  thick  sheet  cork  is  used  on  the  bottom,  two  layers  2-inch  thick  sheet 
cork  on  the  ends  and  sides,  and  one  layer  2-inch  sheet  cork  on  the  top. 
The  double  row  cabinets,  however,  in  order  to  stay  within  the  30  inches 
width,  have  one  layer  2-inch  and  one  layer  IJ/^-inch  sheet  cork  on  the 
ends  and  sides. 

Manufactured  by   Servel   Corporation,   Evansville,   Indiana. 


ABSOPURE  ELECTRIC  ICE  CREAM  CABINET. 

Description. — The  accompanying  photograph  shows  the  cover- 
ing removed  from  the  ice  cream  can  section  of  an  Absopure  4-hole, 
in   line,   self-contained,   air-cooled   electric   ice   cream   cabinet,   display- 


FIG.    191.— ABSOPURE    4-HOLE,    IN    LINE,    SELF-CONTAINED.    AIR-COOLED 

ELECTRICAL  ICE  CREAM   CABINET    (COVERING   REMOVED 

SHOWING   CORKBOARD   INSULATION). 

ing  the  sturdy  framework  of  steel,  the  solidly  placed  pure  com- 
pressed corkboard  insulation  and  the  position  of  the  refrigerating 
coils. 

Insulation. — The  insulation  of  this  unit  consists  of  two  layers 
3-inch  thick  pure  compressed  corkboard  on  the  bottom  of  the  cabi- 
net, two  layers  2-inch  thick  pure  compressed  corkboard  on  the  ends 
and  sides  of  the  cabinet,  and  one  layer  2-inch  thick  pure  compressed 
corkboard  in  the  cabinet  top.  This  insulation  is  carefully  pressed 
into  position,  using  a  waterproof  sealing  material  on  all  joints  and 
surfaces  to  obviate  the  possibility  of  the  collection  and  freezing 
of  water  within  the  cabinet  construction,  due  to  the  condensation  of 
moisture  from  concealed  air  spaces  or  pockets,  and  the  consequent 
disintegration    of    the    insulation,    damage    to    the    cabinet    and    serious 


400  CORK  INSULATION 

loss  of  efficiency  in  operation.  Such  spaces  that  cannot  be  effectively 
sealed  with  corkboard  sheets,  are  packed  tight  with  a  special  water- 
proof sealing  material  combined  with  a  suitable  proportion  of  pre- 
pared cork  particles. 

Maintenance  Cost. — It  is  believed  that  the  construction  of  this 
cabinet  is  an  effective  guarantee  of  lowest  power  and  maintenance 
costs,  when  operated  in  conjunction  with  the  Absopure  refrigerating 
unit. 

Manufactured  by  the  General  Necessities  Corporation,  Detroit, 
Michigan. 

162. — Notes  on  How  to  Test  Ice  Cream  Cabinets. — There 
are  no  generally  accepted  and  approved  methods  for  the  test- 
ing of  either  ice  and  salt  cabinets  or  mechanical  ice   cream 
cabinets,  and  most  all  tests  made  thus  far  are  subject  to  more 
or  less  inaccuracies  and  interpretation  as  to  the  meanings  of 
the  results  obtained.     For  instance,  as  mentioned  for  house- 
hold  refrigerators,   it   has   been    for   years   a   well-understood 
fact  in  the  cold  storage  industry  that  the  efficiency  of  a  new 
cold  storage  room  is  in  itself  of  ver}'  minor  importance,  if  of 
any  real  importance  at  all.     What  is  important  to  the  owners  i 
and  operators  of  large  cold  storage  plants,  is  what  the  effi-  j 
ciency  of  that  room  will  be  one  year  or  ten  years  after  it  has 
been  in  operation ;  for  it  is  possible  to  construct  hollow  walls 
of  wood,   fill   the   space  with   chimney   soot  and   show  under 
accurate   test   an    initial    cold    room   insulating   efficiency    far 
greater  than  could  probably  be  shown  with  any  commercial 
insulating  material  procurable,  }et  the  soot  would  retain  its 
remarkable  efficiency  for  a  very  short  time  only.     Glass  wool, 
fluxed  limestone,  wood  flour,  medicinal  cotton,  nail  polish,  and  \ 
many  other  materials*  in  common  use,  are  very  efficient  ther-  i 
mal  insulators,  but  quickly  lose  their  heat  retarding  properties 
by   settling  and  packing  down  and  by   saturation  with   con-  | 
densed  water  vapor,  if  used  in  connection  with  cold  tempera-  j 
tures. 

The  first  point  to  cover  in  planning  for  tests  of  any  ice  ; 


*In  a  number  of  the  "Berichte"  (1899),  Prof.  Hempel  describes  a  series  of  experi- 
ments undertaken  by  him,  in  order  to  determine  which  substance  was  best  suited 
for  isolating  freezing  mixtures  in  experimental  wcirk  in  the  laboratory.  Starting 
with  a  temperature  of  about  -75°  to  -80°  C.  (-103°  to  -112°  F.)  produced  by  solid 
carbon  dioxide  and  ether,  the  rate  of  rise  of  temperature  with  time  was  measured, 
and,  as  a  result,  eiderdown  was  found  to  be  the  lust  irsiilator.  woo',  carefully  dried 
at  100°  C.  (212°  F.)  being  nearly  as  good,  and  having  the  advantage  of  cheapness. 
Thus  wi"tfi  eiderdown  a  rise  of  12°  C.  occurred  in  eighty-eight  minutes,  with  dry  wool 
a  rise  of  20°   to  24°    C.   in  the  same  time. 


» 


CORKBOARD  ICE  CREAM   CABINET  401 

cream  cabinet  must  tlierefore  he  a  careful  investigation  and 
research  into  the  ability  of  the  insulating  material  to  retain 
its  initial  insulating  efficiency  under  the  conditions  of  its  appli- 
cation in  the  walls  of  the  cabinet  and  for  an  indefinite  period 
of  time  under  known  or  anticipated  conditions  of  service.  If 
such  research  rexeals  that  the  insulation  cannot  be  expected  to 
stand  up  under  the  conditions  to  be  imposed,  there  probably 
will  be  fewer  reasons  for  going  ahead  with  the  plans  to  test 
out  the  cabinet. 

Ice  cream  cabinet  service  is  much  more  severe  than  the 
service  that  household  refrigerators  receive.  Thus  the  proper 
insulation  to  use  and  the  correct  specifications  to  be  followed 
in  installing  it,  are  of  much  more  importance  in  the  ice  cream 
cabinet  than  they  are  in  units  that  operate  at  considerably 
higher  temperatures.  The  experience  of  the  dairy  and  ice 
cream  industries  for  the  past  several  decades  in  the  insulation 
and  operation  of  refrigerated  milk  rooms,  cream  rooms,  ice 
storage  rooms,  hardening  rooms,  antl  cold  rooms  in  general, 
is  of  value  as  research  into  the  fitness  or  lack  of  fitness  of  any 
insulating  material  for  ice  cream  cabinet  construction  and 
temperatures.  I'ure  corkboard  is  the  standard  material  for  all 
such  rooms  in  countless  plants  all  over  the  United  States,  the 
reason  for  which  was  elaborated  in  the  section  of  this  text  on 
"The  Insulation  of  Ice  and  Cold  Storage  Plants  and  Cold 
Rooms  in  General,"  and  which  amounts  to  the  fact  that  cork- 
board  is  the  onl)-  suitable  material  employed  for  such  purpose 
that  when  intelligently  installed  will  retain  approximately  90 
per  cent  of  its  initial  insulating  efficiency  for  ten  years  or 
more. 

I  In  testing  various  kinds  and  sizes  of  corkboard  insulated 

ice   and   salt   cabinets,   assuming   that   virtually   the   same   or 

'  equally  satisfactory  specifications  were  followed  in  installing 
the  corkboard  in  the  cabinets,  and  assuming  that  the  results 
are   to   be   made    available   for   general    comparison   with    the 

I'.i  results  of  other  tests  made  at  different  times  and  places,  the 
following  conditions  sh(ndd  be  obserxed  : 

(a)  A  constant  temperature  room  should  be  used,  the  temperature 
[  held  uniform  to  within  one  degree  Fahr.  hy  electric  heater  placed  within 
||    hollow  walls  of  the  test  room  and  controlled  hy  thermostat. 


402  CORK  INSULATION 

(b)  Control  of  the  humidity  of  the  constant  temperature  room  should 
be  effected  by  suitable  means,  tests  having  demonstrated  that  a  consider- 
able increase  in  the  percentage  of  ice  melting  is  effected  by  increasing  the 
percentage  of  relative  humidity  in  a  constant  temperature  room  from  a 
low  to  a  high  point. 

(c)  The  mixture  of  ice  and  salt  should  be  carefully  regulated  on  the 
basis  of  weight. 

(d)  The  salt  should  be  of  standard  specifications. 

(e)  The  ice  used  should  be  only  hard,  "black"  ice,  and  should  be 
crushed  to  uniform  size.  The  finer  the  ice  is  crushed  and  the  more  salt 
used,  the  lower,  within  limits,  will  be  the  resultant  temperature. 

(f)  Ice  and  salt  should  be  mixed  thoroughly  in  suitable  mixing  box 
located  outside  the  test  room,  and  packed  in  the  ice  cream  cabinet  during  a 
fixed  period,  at  the  same  hour,  every  other  day  (48-hour  icing),  no  ice 
and  salt  to  be  put  on  top  of  cans  and  brine  to  be  drained  off  cabinet  before 
each  re-icing. 

(g)  The  ice  cream  to  be  used  for  test  purposes  should  be  a  product  of 
rigid  specifications,  because  different  mixtures  and  flavors  require  differ- 
ent temperatures  to  keep  them  in  satisfactory  condition,  and  the  volume 
of  ice  cream  in  the  cabinet  should  be  a  fixed  quantity. 

(h)  Special  long-bulb  thermometers  should  be  used  in  ice  cream  cabi- 
nets, of  such  length  as  to  obtain  average  temperature  readings  for  the 
total  depth  of  the  ice  cream  and  for  the  empty  can  of  each  cabinet. 

(i)  Four  days  preliminary  operation  should  be  allowed  to  establish 
a  temperature  equilibrium  in  the  walls  of  the  cabinet  before  the  test  proper 
should  be  started,  and  the  test  should  then  continue  for  30  more  days. 

Tests  performed  under  standardized  conditions  thus  sug- 
gested, values  for  such  standards  to  be  fixed  upon  a  practical 
basis  for  test  purposes  and  a  basis  most  nearly  conforming  to 
the  practices  of  the  ice  cream  industry,  should  be  comparable, 
as  to  ice  consumption,  cabinet  air  temperature,  ice  cream  tem- 
perature, and  condition  of  the  ice  cream  throughout  the  test. 

An  electric  ice  cream  cabinet  may  be  tested  in  much  the 
same  fashion,  the  electric  power  consumption  by  the  cabinet 
machine,  instead  of  the  ice  consumption,  being  comparable 
with  results  of  other  electric  cabinet  tests. 


CHAPTER  XVIII. 
THE  REFRIGERATED  SODA  FOUNTAIN 

163. — Automatic  Operation  of  an  Intricate  Unit  Made  Pos- 
sible with  Corkboard  Insulation. — Soda  fountain  design  has 
kept  well  abreast  of  all  modern  trends  and  developments  in 
automatic  carbonation,  mechanical  refrigeration,  scientific  in- 
sulation, pure  food  preservation,  efficient  operation,  and  rapid 
dispensation  of  popular  delectation.  And  as  a  result  the 
"fountain"  is  popular.  Few  of  its  patrons  probably  realize, 
however,  that  the  modern  soda  fountain  is  an  intricate  and 
delicate  assembly  of  beautiful  store  fixture,  refrigeration  plant, 
cold  storage,  chemical  plant,  and  food  and  drink  dispenser. 
Five  different  temperature  zones  must  be  automatically  estab- 
lished and  accurately  maintained ;  and  all  in  a  space  often  less 
than  a  dozen  feet  long  and  a  quarter  as  high  and  wide!  The 
modern  soda  fountain  deserves  admiration ;  its  successful  op- 
eration is  made  possible  by  permanently  efficient  corkboard 
insulation,  scientifically  adjusted  to  the  service  desired. 

For  it  is  one  thing  to  produce  refrigeration,  and  another 
thing  to  conserve  it  and  apply  it  to  good  purpose.  When  a 
quarter-score  temperatures  must  be  maintained  and  controlled 
within  such  narrow  confines  as  twenty  cubic  feet,  the  cold 
storage  problem  takes  on  a  new  interest  and  importance  in- 
deed. Corkboard  insulation,  properly  utilized,  permits  of  the 
most  delicate  and  accurate  operation  of  the  most  modern  soda 
fountain,  just  as  it  has  been  of  so  much  use  and  assistance 
wherever  temperatures  below  that  of  the  atmosphere  are  arti- 
ficially produced,  efficiently  maintained  and  advantageously 
utilized. 

164. — Extracts    from    Manufacturers'    Specifications*    for 


•Descriptions    are    those    of    the    manufacturer,    and    arc    to    be    accepted    only    for 
what  they  may  prove  to  be  worth. 

403 


404 


CORK  INSULATION 


Modern  Mechanically  Refrigerated  Soda  Fountain  with  Typi- 
cal Details  of  Construction. — Tlie  foUuwini;'  excerpts  from  a 
manufacturer's  complete  soda  fountain  specification  are  pre- 
sented to  illustrate  the  scope  of  the  work  of  designing  and 
l:)uilding"  such  equipment,  in  which  corkboard  insulation  plays 
such  an  important  part ;  by  courtesy  of  The  Bastian-Blessing 
Company,  Chicago,  Illinois,  and  Grand  Haven,  Michigan  : 

DETAILS    OF    SODA   FOUNTAIN    CONSTRUCTION. 

Note  the  heavy  construction  throughout  and  the  unexcelled  cork  insu- 
lation. There  are  4-inch  walls  all  around,  front,  bottom,  back  and  two 
ends.  These  walls  are  provided  with  3-inch  pressed  pure  corkboard  insu- 
lation. To  correctly  understand  this  construction  is  to  appreciate  the 
superiority  of  the  material  and  workmanship,  and  the  correctness  of  the 
fundamental  principles  empkned  in  the  construction  of  the  Guaranty 
fountains. 


IG.    192.— Si:CTIOX.\L    \"IEW    OF    FOL'-XTAIX    CABIXET. 


1.  Raised   edge   creamer  capping  and   top   in   one  piece,    16-gauge   nickel   silver. 

2.  3-inch   removable    top    insulated   with    2-inch   pressed   pure    corkboard. 

3.  Fabric  base   special   non-conductor   practically   prevents   all   refrigeration   loss. 

4.  K'o.    IS'  porcelain   white   enamel   Armco   iron   front;    can   also   be   faced   with    7/16 
vitrolite   or   marble,   when   specified. 

5.  1-inch  waterproof  cypress  wall. 

6.  3-inch  pressed   pure  corkboard   insulation. 


REFRIGERATED  SODA  FOUNTAIN  405 

7.  20-ounce   hot    rolled    copper    lining   of   brine   compartment. 

8.  Brine    solution. 

9.  32-ounce  hot  rolled  tinned  copper  ice  cream  tanks  with  galvanized  copper  steel 
sleeve. 

10.  Strong  adjustal)Ie  legs,  .screwed  in  brass  flanges  bolted  through  creamer 
bottom. 

11.  Special   non-conductor   frame   practically   eliminates   all   sweating. 

12.  Double  acting  nickel  silver  hinged  lid  insulated  with  1-inch  pressed  pure 
corkboard. 

13.  Removable    gutter    easily    cleaned. 

14.  No.    18   porcelain   white   enamel   Armco   iron   facing   for   syrup  jar  enclosure. 
l.S.      1-inch   waterproofed   cypress   wall. 

16.  16-ounce    cold    rolled   tinned   copper   lining  in   syrup  unit. 

17.  Special    non-conductor,    breaking   all    metal    to    metal    contact    with    the    outside. 

18.  Nickel   silver   syrup   unit  capping. 

19.  Open   gutter,   to   take   off  draft   arm   spillage,   easily   cleaned. 

20.  Waterproof  airtight   seal. 

21.  Solid  2x3   inches  interlocking  frame. 

22.  Metal  conductor  strips  insure  positive  and  constant  refrigeration  of  syrup 
unit. 

23.  Dead   air   space   forming   additional   insulation. 

24.  Heavy  copper  bearing  steel  facing  bottom,  back  and  ends. 

Complete  Refrigeration  With  One  Frigidaire  Unit. 

The  application  of  mechanical  refrigeration  to  soda  fountains  required 
considerable  study,  many  experiments  and  much  caution.  Mechanical  re- 
frigeration in  itself  was  nothing  new  and  had  been  in  commercial  use 
for  many  years.  However,  its  application  to  the  soda  fountain  at  once 
brought  out  the  difficulty  of  supplying  the  many  temperatures  needed  for 
the  successful  operation  of  these  fountains  with  one  refrigerating  unit. 

In  designing  the  Guaranty  fountain  in  its  simple  and  practical  way  to 
secure  the  five  necessary  temperatures,  the  engineers  have  scored  a  com- 
plete triumph. 

The  many  months  spent  in  experimenting,  simplifying  and  in  other 
ways  adding  to  the  all-around  efficiency  of  this  type  of  fountain,  resulting 
in  the  100  per  cent,  mechanically  refrigerated  Guaranty,  was  well  worth 
while.  The  operation  of  thousands  of  these  fountains  in  every-day  use 
has  completely  demonstrated  not  only  Guaranty's  ability  to  serve  supremely 
well  and  economically,  but  also  to  deliver  many  years  of  continuously 
satisfactory  service. 

Maintaining  Five  Correct  Temperatures  Automatically. 

The  Guaranty  soda  fountain  is  constructed  in  a  simple  and  practical 
way  to  secure  the  five  necessary  soda  fountain  temperatures. 

The  soda  and  city  water  coolers  and  the  Frigidaire  boiler,  located  in 
the  first,  or  cooling  chamber,  are  immersed  in  a  water  bath  as  shown 
more  clearly  in  the  sectional  view.  Fig.  199.  The  temperature  is  auto- 
matically maintained  at  approximately  33°  F.  by  a  regulating  control  valve. 

The  dry  storage  refrigerator  is  located  second  from  the  left  in  which 
a  temperature  ranging  from  40°  to  45°  F.  is  maintained.  This  compart- 
ment is  equipped  with  a  sliding  shelf,  thus  providing  double-deck  arrange- 
ment for  bottle  goods.  Refrigeration  for  this  compartment  is  secured 
through  a  semi-insulated  partition  from  the  cooling  compartment. 

On  the  extreme  right  is  located  the  brick  compartment,   where  a 


406 


CORK  INSULATION 


REFRIGERATED  SODA  FOUNTAIN  407 

temperature  of  0°  to  5°  F.  is  maintained.  The  Frigidaire  boiler  producing 
this  temperature  is  automatically  controlled  by  the  compressor  itself. 

Separating  the  brick  compartment  from  the  bulk  compartment  at  its 
left  is  a  correctly  proportioned  baffle  partition  which  permits  the  exact 
amount  of  refrigeration  in  order  that  the  bulk  cream  may  be  kept  at  a 
temperature  of  from  ten  to  twelve  degrees  above  zero. 

The  syrup  unit  secures  its  refrigeration  through  copper  conductor 
plates  attached  to  the  bottom  of  the  syrup  unit  lining  and  extending  down 
into  the  brine  of  the  bulk  compartment.  The  refrigeration  necessary  to 
produce  a  temperature  of  from  twenty  to  thirty  degrees  under  the  room 
temperature  of  from  ten  to  twelve  degrees  above  zero.  The  bulk 
compartment  and  storage  refrigerator  are  separated  by  a  2i/2-inch 
corkboard  partition. 

Study  well  the  illustrations  in  Fig.  193.  Take  note  of  the  arrange- 
ment and  the  method  and  system  of  operation  of  the  refrigerating  unit, 
and  remember  that  continuous  operation  and  efificient  functioning  requires 
the  utmost  in  simplicity  and  practicability  of  construction,  all  so  clearly 
shown  in  Fig,  193. 


FIG.    194.— CORKBOARD    INSULATED    CREAMER. 

Creamer. 

Frame. — Constructed  of  genuine  Louisiana  red  cypress,  a  product  of 
the  Southern  swamps,  inured  to  all  kinds  of  weather,  accustomed  to  moist- 
ure and  exposure  and,  above  all,  possessing  a  long  life.  Front  and  rear 
paneled,  tenoned,  glued  and  nailed  to  a  chestnut  supporting  frame,  all 
thoroughly  impregnated  with  preservative  paint,  making  it  truly  the  "box 
eternal." 

Insulation. — In  addition  to  the  1-inch  cypress  walls  the  insulation  con- 
sists of  3-inch  pressed  pure  corkboard,  all  joints  cemented  with  a  spe- 
cially prepared  cork  cement,  making  a  jointless  wall.  Insulating  qualities 
of  corkboard  are  based  on  the  natural  quality  of  the  cork  plus  the  dead 
air  space  so  long  in  use  as  a  barrier  of  heat.  The  cork  is  pressed  into 
a  board  under  heat  and  the  natural  resin  cements  the  cork  together,  impris- 


408  CORK  INSULATION 

oning  millions  of  tiny  dead  air  cells  forming  a  veritable  deadline  against 
the  entrance  of  heat  into  the  soda  fountain. 

Ice  Cream  Compartment  Linings.— AW  materials  that  enter  into  the 
construction  of  the  Guaranty  are  selected  with  a  view  to  securing  the 
best  for  the  use  intended.  Tests  and  experiments  have  fully  and  clearly 
demonstrated  that  copper  is  the  most  practical  and  durable  for  soda  foun- 
tain linings.  The  Guaranty  fountain  is  lined  with  20-ounce  hot  rolled 
copper,  front,  bottom  and  back  in  one  piece.  Ends  are  double  seamed, 
interlocked  and  soldered.  The  bottom  is  reinforced  with  20-gauge  Key- 
stone copper-bearing  steel  to  insure  greater  strength  and   resistance. 

Tank  and  Sub-Covers. — Water-tight  tanks  and  sub-covers  are  required 
to  hold  the  ice  cream  cans.  Tank  bodies  are  made  of  32-ounce  hot  rolled 
tinned  copper  and  have  one  vertical  double  seam  soldered  on  the  outside. 
Tank  bottom  is  also  32-ounce  hot  rolled  tinned  copper  and  is  double 
seamed  and  soldered  to  the  bodies.  A  galvanized  copper-bearing  steel 
sleeve  extending  6  inches  down  into  the  tank  is  soldered  to  it.  This  sleeve 
protects  the  copper  and  prevents  dents,  or  perhaps  punctures  from  care- 
lessness in  removing  or  inserting  the  ice  cream  cans.  The  complete  tanks 
are  sweated  to  a  sub-cover  made  of  32-ounce  hot  rolled  copper. 

The  sub-cover  has  the  proper  number  of  oval  openings  carefully 
machine  stamped  and  also  has  an  opening  through  which  the  coil  can  be 
removed  should  it  ever  become  necessary. 

In  the  bottom  of  each  tank  there  is  placed  a  20-gauge  galvanized 
copper-bearing  steel  plate  as  additional  reinforcement  to  prevent  the  tank 
bottom  from  being  dented  when  the  ice  cream  cans  are  dropped  into  place. 

After  the  tank  and  sub-cover  unit  have  been  assembled  as  described, 
it  is  placed  into  the  creamer  box  and  the  sub-cover  is  sweated  to  the 
lining.  The  Frigidaire  boiler  is  then  installed  and  the  entire  unit  is  filled 
with  water  and  tested  for  leaks. 

Cooler  and  Dry  Storage  Refrigerator.  —  An  integral  part  of  the 
creamer,  separated  from  the  ice  cream  compartment  by  2^-inch  cork 
partition;  lined  with  16-ounce  cold  rolled  copper  tinned  one  side,  front, 
bottom  and  back  in  one  piece,  ends  double  seamed,  interlocked  and  soldered. 
This  compartment  is  divided  by  a  semi-insulated  partition.  One  side  con- 
tains a  water  bath  and  refrigerating  coil  for  cooling  soda  and  city  water 
and  the  other  side  is  a  dry  storage  compartment  which  secures  its  refrig- 
eration through  the  semi-insulated  partition.  An  outlet  with  an  overflow 
pipe  topped  with  a  funnel  is  provided  to  drain  the  syrup  unit  and  cooler 
compartment  when  necessary. 

Brick  Compartment. — This  compartment  is  separated  from  the  bulk 
cream  compartment  by  a  metal  baffle  partition.  This  compartment  con- 
tains the  boiler  which  is  regulated  to  maintain  a  temperature  of  approxi- 
mately zero.  All  Guaranty  standard  plans  are  shown  with  one  rectangu- 
lar brick  compartment  with  a  capacity  of  50  one-quart  bricks. 

Bulk    Compartment. — The    correctly    proportioned    metal    baffle   which 


REFRIGERATED  SODA  FOUNTAIN  409 

separates  ihe  brick  and  bulk  compartments  retards  refrigeration  sufficiently 
to  produce  a  tcmiierature  of  from  8  to  12  degrees  above  zero  in  the  bulk 
compartment. 

Frigidairc  Coils. — In  order  to  suppl\  100  per  cent,  mechanical  refrig- 
eration under  ])ositivc  automatic-  control,  two  coils  and  one  regulating 
valve,  in  addition  to  the  compressor  suitable  for  the  refrigeration  of  the 
creamer,  arc  required  in  all  cases. 

The  standard  installation  consists  of  one  coil  for  suppl\ing  refrigera- 
tion to  the  cooler  and  cold  storage  compartment,  and  one  coil  for  the 
refrigeration  of  the  ice  cream  compartments.  They  are  installed  at  the 
factory  in  a  neat  and  workmanlike  manner  and  the  entire  tank  is  tested 
for  leaks  before  it  leaves  the  plant.  All  Guaranty  interiors  are  equipped 
at  the  factory  with  the  standard  installation  of  coils  and  shipped  complete 
with  the  regulating  valve. 

Facings. — Front  is  faced  with  No.  18  Armco  Iron  with  three  coats  of 
white  porcelain  enamel  fired  at  a  temperature  above  1700°  F.  All  facings 
are  made  to  exact  dimensions  before  coating,  and  there  are  never  any 
crazed  edges  so  often  found  when  sheared  to  size  after  being  enameled. 
Both  ends,  bottom  and  back  arc  covered  with  20-gauge  copper-bearing 
galvanized  steel,  coated  with  aluminum  bronze  paint. 

Bindings. — The  bindings  are  20-gauge  nickel  silver,  neatly  made  up, 
attached  with  brass  nickel  plated  screws. 

Adjustable  Legs. — Creamer  units  are  equipped  with  heavy  metal  legs 
adjustable  to  allow  for  ordinary  irregularities  in  the  floor  without  resort- 
ing to  the  use  of  wedges. 

The  legs  arc  fitted  with  rounded  caps  which  provide  a  smooth  sliding 
surface,  and  are  turned  in  heavy  solid  brass  flanges,  securely  fastened  to 
the  creamer  box  with  bf)lts,  which  i)ass  through  the  entire  thickness  of  the 
creamer  bottom. 

FIG.    195.— CORIvBO.\RD    INSULATED    CREAMER    TOP. 

Creamer  Top. 

Frame— L\ke  the  creamer  box,  the  frame  of  the  top  is  constructed  of 
genuine  Louisiana  Red  Cypress,  the  "wood  eternal,"  thoroughly  impreg- 
nated with  a  wood  preservative. 

In.uilafion. — Pure  corkboard  2  inches  thick  is  used  for  insulation.  The 
surface  of  the  cork  is  effectively  sealed  against  moisture  by  a  heavy  coat- 
ing of  hydrolene. 

Capping.— One  solid  piece  of  16-gauge  Grade  A  18%  nickel  silver 
(weighing  approximately  two  pounds  to  the  square  foot)   forms  the  cover- 


41C  CORK  INSULATION 

ing  for  the  top.  The  front  edge  is  raised  and  beveled  to  prevent  water 
from  dripping  on  the  floor.  Machine  cut  oval  openings  provide  access  to 
the  ice  cream  cans  and  a  rectangular  opening  to  the  cooler  and  cold  stor- 
age compartment.  A  raised  rim  in  each  oval  opening  prevents  seepage 
into  tanks  and  ice  cream  cans. 

Non-Conductor. — Great  care  was  exercised  in  the  selection  of 
Guaranty  Non-Conductor.  After  countless  experiments  had  determined 
that  Bakelitc  with  a  fabric  base  possessed  the  needed  strength,  ability 
to  withstand  moisture  and  above  all,  had  the  required  insulating  property, 
it  was  chosen  for  use  with  Guaranty 'soda  fountains  and  the  actual  opera- 
tion of  these  fountains  in  daily  use  has  fully  justified  this  selection. 

Removable  Gutter. — Leakage  through  the  hinge  of  the  twin  packer  lid 
has  not  been  overcome  nor  completely  eliminated  by  anyone.  In  some 
cases  the  covers  have  been  built  up  to  such  a  height  that  most  of  the 
water  can  be  carried  off  to  the  top  of  the  creamer.  The  height  of  this 
projection  or  of  the  complete  cover  itself,  hinders  ease  in  operating  and 
cleaning,  besides  which  it  is  unsightly.  The  Guaranty  solution  of  the 
problem  consists  of  a  removable  gutter  attached  to  lugs  directly  under- 
neath the  hinge,  as  shown  in  Fig.  192.  What  little  water  has  occasion  to 
seep  through  the  lid  is  caught  by  this  gutter  and  its  removal  and  sub- 
sequent cleaning  is  both  simple  and  easy.  At  the  same  time,  a  beautiful 
smooth  and  even  creamer  top  is  maintained. 

Twin  Packer  Cover. — An  ingenious  hinged  cover  divided  in  the  center 
provides  access  to  both  ice  cream  cans,  making  each  can  a  dipping  can. 
This  cover  folds  back  completely  either  way  so  that  both  cans  can  be 
emptied  completely  without  removing  the  front  can  and  bringing  the  rear 
can  forward  as  is  necessary  in  so  many  other  types. 


FIG.  196.— CORK  INSULATED  TWIN  PACKER  COVER. 

Non-Conductor  Lid. — The  operation  of  the  twin  packer  cover  is  shown 
above,  and  the  accompanying  illustration  shows  this  lid  in  complete  detail. 
It  is  made  with  a  frame  of  special  insulating  material,  strong,  durable  and 
non-absorbent.  The  lid  top  is  14-gauge  nickel  silver,  fastened  to  the  non- 
conductor   frame    with    nickel    silver    brackets    electrically    welded    to    the 


REFRIGERATED  SODA  FOUNTAIN 


411 


underside  of  the  top.  It  is  insulated  with  one  inch  of  pressed  pure  cork- 
board,  and  a  nickel  silver  bottom,  binding  the  entire  cover  together,  is 
sprung  into  a  groove  in  the  non-conductor  frame.  The  front  and  rear 
half  are  each  provided  with  rubber  tipped  knobs,  doing  away  with  the  old 
thumb  nip,  thus  eliminating  the  slight  opening,  and  providing  additional 
precaution  against  refrigeration  loss,  at  the  same  time  making  the  operation 
of  these  covers  easy  and  noiseless.  The  illustration  shows  clearly  that  all 
metal  to  metal  contact  is  broken  practically  eliminating  all  refrigeration 
loss. 


FIG.    197.— INSULATED    SYRUP    UNIT. 

Syrup  Unit. 

Frame. — The  usual  unbeatable  Louisiana  red  cypress  is  used  in  the 
construction  of  the  syrup  unit  frame.  The  bottom  is  5-ply,  ^-inch  Haske- 
lite  panel  board,  which  gives  the  necessary  strength  to  insure  that  quality 
of  endurance. 

Non-Conductor. — Wherever  it  has  been  necessary  Guaranty  soda 
fountains  are  equipped  with  special  non-conductor  to  practically  eliminate 
all  refrigeration  loss.  The  syrup  unit  is  so  constructed,  and  special  non- 
conductor strips,  completely  breaking  all  metal-to-metal  contact  with  the 
outside,  are  provided  in  the  con.slruction,  as  shown  by  the  accompanying 
illustration. 

Drain  for  Draft  Arm  Spillage. — All  Guaranty  interiors  are  constructed 
with  an  open  drain,  leading  from  the  drip  pan  to  the  creamer  outlet.  This 
is  attached  to  the  rear  syrup  unit  wall,  a  convenient  and  out  of  the  way 
location.  No  spillage  resulting  from  mixing  drinks  at  draft  arms  reaches 
the  syrup  jar  enclosure  bottom,  making  it  easy  to  keep  dry  and  clean. 

Lining. — 16-ounce  pure  cold  rolled  tinned  copper  forms  the  lining, 
made  of  one  piece  with  ends  double  seamed  and  soldered. 

Capping. — The  front  rail  and  top  capping  are  heavy  Grade  A  18% 
nickel  silver. 


412 


CORK  INSULATION 


Adjusliiii)  Plates. — The  product  of  the  best  porcchin  manufacturers 
in  the  country  is  used,  but  it  is  impossible  to  guarantee  absolute,  precise 
uniformity  in  jar  sizes. 

In  order  to  insure  a  perfect  fit,  adjusting  plates  are  provided  at  each 
end  of  the  syrup  unit  to  take  up  any  excess  opening.  These  are  stamped 
of  18-gauge  nickel  silver. 

Facing. — The  ends  are  faced  with  No.  18  ])orcelain  white  enamel 
Armco  iron,  the  back  with  galvanized  copper-bearing  steel  painted  with 
aluminum  bronze. 


I'K;.    198.— cork    IXSULATKD    DRAl-T    ARM. 


Filler  Iiilcls.—hi  the  bottom  of  the  syrup  unit  and  directly  to  the  rear 
of  the  boiler,  provision  is  made  for  filling  the  outfit  with  brine  or  for  in- 
serting a  siphoning  hose  should  it  ever  become  necessary  to  remove  the 
brine.  These  consist  of  heavy  brass  ^-inch  filler  tubes  just  long  enough 
to  extend  through  the  sub-cover.  The  upper  end  is  threaded  on  the  inside 
to  fit  a  brass  plug.     Convenient  and  out  of  sight. 

Workboards. 

Clear  Counter  Service  Cork  Insulated  Draft  Arms.— The  draft  arms 
used  in  all  Guaranty  interiors  are  as  shown  in  the  accompanying  illustra- 
tion.     They   are   made   of   bronze,   heavily   silver   plated,   hand   burnished, 


REFRIGERATED  SODA  FOUNTAIN 


413 


and  are  supplied  with  block  tin  tubing  for  the  passage  of  the  carbonated 
water  through  the  draft  arm  to  the  head.  Refrigeration  loss  is  reduced  to 
a  minimum  by  the  cork  insulation  which  is  used.  The  soda  and  city  water 
after  it  leaves  the  coolers  travels  through  the  refrigerated  syrup  unit  and 
is  connected  directly  to  this  cork  insulated  Guaranty  draft  arm.  In  the 
design  of  these  draft  arms  all  sharp  lines  are  eliminated,  thus  avoiding 
the  premature  wearing  of  silver  plating  through  the  ordinary  process  of 
polishing. 

The  soda  leader  pipes  running  from  the  coolers  to  the  draft  arms  are 
equipped  with  individual  shut-ofif  valves  for  each  draft,  thereby  making  it 
possible  to  replace  a  tumbler  or  washer  when  necessary  without  turning 
off  the  entire  service  supply.  These  valves  are  located  at  a  convenient 
point  in  the  syrup  unit,  and  are  readily  accessible. 

Cooling  System. 

Soda  and  city  water  in  all  Guaranty  interiors  are  cooled  by  what  was 
formerly  known  as  the  Iceless  system,  or  since  the  advent  of  mechanical 
refrigeration  as  the  100%  method.  This  consists  of  coolers  submerged  in 
a  fresh  water  bath,  cooled  by  a  boiler  used  in  connection  with  the  refrig- 
eration unit  which  is  used  to  refrigerate  the  ice  cream. 


199.— COOLER  AND  BOILER  ARRANGEMENT,  56-IN.  AND  64-IN. 
GUARANTY  BOXES. 


The  refrigerator  section  is  divided  into  two  compartments  by  a  semi- 
insulated  partition ;  one  for  cooling  soda  and  city  water,  known  as  the 
cooler  compartment ;  the  other  provides  cold  storage  facilities  for  bottled 
goods,  etc.,  known  as  the  cold  storage  compartment.  In  the  56-inch  and 
64-inch  tall  and  squat  and  77-inch  and  82-inch  squat  creamers,  the  coolers 
arc  located  at  the  rear  of  the  cooler  compartment  with  the  Frigidaire  boiler 


414  CORK  INSULATION 

exactly  in  front  center.  In  all  of  the  other  creamers,  the  coolers  are  placed 
on  each  side  of  the  cooler  compartment  with  the  Frigidaire  boiler  between 
them.  The  boiler  and  coolers  are  submerged  in  a  water  bath;  jce  forms 
around  the  boiler  cooling  the  water  bath  and  in  turn  the  soda  and  city 
water. 

The  refrigeration  is  controlled  by  an  automatic  regulating  valve  located 
at  the  end  of  the  creamer,  directly  under  the  drainboard.  A  temperature 
sufficiently  low  is  maintained,  but  controlled  to  prevent  freezing. 

The    balance    of    the    refrigerator    compartment    furnishes    dry    cold 


FIG.  200.— COOLER  AND  BOILER  ARRANGEMENT,  ALL  OTHER 
GUARANTY  BOXES. 

Storage  for  bottled  goods,  etc.  It  secures  its  refrigeration,  through  the 
semi-insulated  wall  from  the  cooler  compartment,  and  there  is  no  difficulty 
in  maintaining  the  correct  temperature  for  this  compartment. 

Coolers. — In  the  56-inch  and  64-inch  creamer  boxes  is  provided  a  6- 
cylinder  upright  soda  cooler  installed  to  the  rear  of  the  Frigidaire  boiler. 
In  all  other  creamers  is  provided  a  S-cylinder  soda  cooler  19  inches  long. 
Either  of  these  coolers  has  ample  capacity  to  assure  cold  water.  The 
outside  wall  of  these  coolers  is  heavily  tinned,  seamless  copper  tubing;  the 
inside  lining  is  of  pure  seamless  block  tin  tubing  with  die  cast  tin  ends. 
All  coolers  are  thoroughly  tested  under  heavy  pressure  before  they  leave 
the  factory.  There  are  absolutely  no  flexible  connections  to  become  twisted, 
choked  or  broken.  Carbonated  water  passes  through  the  series  of  cylinders 
and  is  finally  drawn  from  the  top  cylinder.  The  Guaranty  iceless  coolers 
reduce  wear  and  tear  to  a  minimum  and  are  properly  designed  and  con- 
structed to  insure  cold  soda  water. 

The  water  cooler  used  is  the  same  style  and  capacity  as  that  for  the 
soda,  except  that  it  is  tinned  inside  instead  of  being  lined  with  block  tin 


REFRIGERATED  SODA  FOUNTAIN  415 

tubing.     This  large  capacity  water  cooler  insures  plenty  of  cold  water  and 
is  a  feature  not  found  in  many  other  makes  of  fountains. 

Syrup  System. — The  syrup  unit  is  one  of  the  most  important  features 
of  the  soda  fountain,  the  effectual  operation  of  which  adds  materially  to 
the  right  kind  of  service,  sanitation  and  cleanly  appearance  of  the  fountain 
itself.  It  is  just  as  necessary  to  supply  adequate  refrigeration  for  this  unit 
as  it  is  in  the  balance  of  the  fountain. 


FIG.    201.— COOLER. 


The  Guaranty  fountains'  refrigeration  is  provided  by  means  of  metal 
contacts  between  the  syrup  unit  lining  and  the  lining  of  the  bulk  cream 
compartment.  Wide  copper  conductor  strips  are  attached  to  the  bottom  of 
the  syrup  unit  lining,  the  other  end  of  which  is  submerged  in  the  cold 
brine.  This  metal  contact  is  a  positive  conductor,  and  heat  is  absorbed 
from  the  syrup  unit,  just  as  certain  as  the  fiow  of  electricity  over  copper 
wire.  A  temperature  of  from  20  to  30  degrees  less  than  the  room  tempera- 
ture is  maintained,  and  fruits  and  syrups  never  sour. 

To  conserve  all  of  the  refrigeration  supplied,  a  special  non-conductor 
I  breaks  all  metal  to  metal  contact  with  the  outside,  as  fully  described  and 
1  illustrated  previously. 

^        This  method  of  supplying  refrigeration  to  the  syrup  has  been  success- 
fully used  by  Guaranty  for  years,  and  the  application  of  it  when  used  with 
[;:  mechanical  refrigeration  is  not  only  highly  approved  by  prominent  refrig- 
||i  eration  engineers  but  has  proven  an  outstanding  success  in  actual  use. 

Compressor  Installation  under  Drainboard. — Standard  Guaranty  plans 
shown  contemplate  installation  of  the  Fridigaire  compressor  in  the  base- 
ment or  other  convenient  place,  removed  from  the  soda  fountain.  Where 
this  is  impossible  and  it  is  necessary  to  keep  the  refrigerating  unit  in  the 
same  room  with  the  soda  fountain,  installation  can  be  made  under  the 
drainboard,  as  shown  in  Fig.  202. 


416 


CORK  INSULATION 


These  compressor  enclosures  are  made  of  paneled  cypress,  contain  a 
floor  for  the  machme  and  are  vented  to  allow  free  circulation  of  air,  which 
not  only  insures  a  dry  enclosure,  but  permits  the  operation  of  the  com- 
pressor to  its  fullest  efficiency.  They  are  faced  with  porcelain  white  enamel 
Armco  iron  to  confirm  to  the  rest  of  the  fountain.  Minimum  plain  drain- 
board  space  required  is  38  inches. 


FIG.    202.— COMPRESSOR    UNDER    DRAINBOARD. 


Backbar  Bases. 

Refrigerator  Bases. — Where  cold  storage  in  addition  to  that  provided 
in  the  interior  is  desired,  bases  can  be  supplied  either  partially  or  wholly 
refrigerated.  Bases  of  this  construction  are  metal  lined  and  equipped  with 
hardwood  racks.  The  bottom,  back,  top  and  both  ends  are  insulated  with 
2-inch  thick  pressed  pure  corkboard,  as  are  the  doors  which  are  of  heavy 
refrigerator  construction  with  stainless  vitrolite  panels.  Bases  constructed 
as  above  are  22  inches  wide  overall. 

The  installation  of  the  Frigidaire  cooling  coils  is  a  simple  matter  and 
consists  of  placing  one  of  the  ordinary  ice  box  coils  in  the  base.  Tiie  unit 
required  depending  on  the  number  of  cubic  feet  it  is  intended  to  refrig- 
erate. The  local  Delco  Light  dealer  can  give  the  desired  information  and 
recommend  the  coil  to  be  used. 

Three  Door  Refrigerator  ijicltiding  Biological  Drawer  Section. — 
Fig.  203  illustrates  a  standard  cabinet  base  with  a  section  refrigerated  by  a 
Frigidaire  remote  installation  as  shown.  A  standard  drawer  section  for 
storage  of  biologicals  is  included.  This  is  a  handy  arrangement  for  use 
in  drug  stores.  The  two  end  cabinets  are  not  refrigerated,  but  these  also 
can  be  included  if  so  desired. 

Three  Door  Refrigerator  Section. — The  base  shown  in  Fig  204  is 
designed  to  accommodate  the  installation  of  the  necessary  compressor  in 
the  base.     A  compact  arrangement  where  no  basement  space  is  available. 


I 


REFRIGERATED  SODA  FOUNTAIN  417 

The  doors  of  the  compressor  enclosure  are  metal  with  ventilating  oi)enings, 
finished  in  baked  white  enamel.  \'rntilator  holes  are  also  provided  thru 
the  back  and  end. 


FIG.    203.— REFRIGERATOR    T.ASE    WITH    BIOLOGICAL    DRAWER    SECTION. 

A   convenient  auxiliary   for  those   soda   fountain  owners  who   require 
much  space  for  storage  of  bottled  goods. 


CROSS    StCTlON    A  ft      , 


FIG.    204.— REFRIGERATOR     BASE    WITH     FKIGHJAIRE    MACHINE 
COMPARTMENT. 

Cubical  contents  of  refrigerated  sections  in  Ijackbar  bases  with  size  of 
Frigidairc  coil   recommended  : 

DIMENSIONS    OF   REFRIGERATED    SECTIONS   AND   COIL    RECOMMENDED. 


Size 


Depth 


Height 


Length 


Cubic  Feet 


Coil 


3  Door  15'/2  inches 

4  Donr  ISyi  inches 

5  Door  LS ',4  inches 

6  Door  L^  J'S  inches 


29  inches  63       inches 

29  inches  35 '/<  inches 

29  inches  ICS       inches 

29  inches  130'/.  inches 


16.4  No.  10 

22.25  No.  12 

2S'.l  No.  14 

34.0  No.  14 


Backbar  Bases  With  Recessed  Ice  Cream  Cabinet. 

When   it   is   not   practical    to   imt   sufficient   ice   cream    cabinets   in   the 
iterior.  the  use  of  this  base  will  be  found  desirable.     The  standard  size  is 


418  CORK  INSULATION 

made  to  take  six  S-gallon  ice  cream  packing  cans  (twin  packer  style  con- 
struction). The  width  overall  of  this  base  is  30  inches.  It  is  regularly 
built  with  cabinet  base  ends  but  may  be  built  with  full  refrigerator  ends 
at  an  additional  price  if  so  specified. 


FIG.   205.— BACKBAR   BASES   WITH   RECESSED  ICE  CREAM   CABINET. 

The  overall  dimensions  of  the  standard  recessed  ice  cream  cabinet  are 
29  inches  high,  28^  inches  deep  from  front  to  back  and  46^  inches  long. 
A  standard  30-gallon  capacity  recessed  ice  cream  cabinet  as  illustrated, 
occupies  the  same  space  as  is  required  for  three  regular  standard  door 
compartments. 

If  squat  cans  are  used  the  overall  width  of  the  base  is  32  inches  and 
the  overall  dimensions  of  the  cabinet  are:  Height,  29  inches;  depth,  30^ 
inches;  length,  49>^  inches. 

The  following  specifications  have  been  extracted,  through 
the  courtesy  of  the  manufacturer,  from  the  literature  of  The 
Liquid  Carbonic  Corporation,  Chicago,  Illinois: 

UNIVERSAL  MECHANICOLD  SODA  FOUNTAIN. 

Fig.  206  is  a  marble  constructed  cooler  box,  insulated  throughout  with 
pure  corkboard.  The  top  capping  is  one  piece  18-gauge  nickel  silver  with 
a  beaded  or  rolled  edge. 

Two  boilers  and  a  control  valve  are  supplied  and  a  Y^  h.p.  Frigidaire 
compressor  is  required  to  operate. 

The  box  has  two  openings  for  bulk  ice  cream  storage.  Each  opening 
is  equipped  with  a  double  hinged  black  insulating  cover  and  is  capable  of 
holding  two  5-gallon  bulk  ice  cream  cans.  This  gives  a  capacity  of  four 
S-gallon  cans  of  bulk  ice  cream  or  20  gallons,  all  of  which  is  maintained 
at  a  uniform  temperature  from  the  top  to  the  bottom  of  the  cans. 

The  extreme  left  hand  opening  is  a  package  storage  compartment 
which  has  a  storage  capacity  of  10  gallons  with  an  insulating  cover  the 
same  as  those  over  the  bulk  ice  cream  compartments.  It  is  maintained  at 
a  special  low  temperature,  around  zero  to  insure  proper  storage  for  pack- 
age ice  cream. 


NOTE— All    references    to   positions    in    illustration    and    diagrams    are    made    as    if 
standing   in   front   of  counter. 


REFRIGERATED  SODA  FOUNTAIN  419 

A  dry  cold  storage  compartment  is  located  next  to  the  attemperating 
chamber.  This  compartment  is  extra  large  and  roomy  being  24x24  inches. 
There  is  ample  room  for  the  storage  of  milk,  grape  juice  and  other  bottled 
goods.  No  ice  is  used  in  this  compartment;  it  is  maintained  at  a  low 
temperature  by  means  of  the  ice  formation  in  the  attemperating  chamber. 

In  the  top  of  this  compartment  is  a  large  size  chipped  ice  pan,  the  drip 
from  which  is  carried  into  an  outlet  pipe,  keeping  the  interior  of  the  cold 


FIG.    206.— UNIVERSAL    MECHANICOLD    SODA    FOUNTAIN    (ONE    STATION 
COOLER  BOX). 

storage  compartment  dry.  If  desired  this  pan  may  be  used  as  a  container 
for  whipped  cream. 

There  are  three  octag6nal  pattern  stamped  silver,  silver-plated,  cork 
insulated,  draft  arms  in  the  center  of  the  box.  The  box  is  also  equipped 
with  14  "Mechanicold"  double  support,  silver-plated  pumps  with  black 
insulating  tops  and  14  white  vitreous  syrup  jars.  In  place  of  any  of  the 
syrup  pumps  a  white  vitreous  two  compartment  spoon  holder  can  be  sup- 
plied. 

If  additional  crushed  fruit  jars  are  required  a  short  jar  can  be  supplied 
to  take  the  place  of  the  regular  syrup  jar.  This  jar  is  equipped  with  a 
black  insulating  hinged  cover  in  which  is  fitted  a  porcelain  name  plate. 
These  covers  are  similar  to  those  used  on  the  crushed  fruit  jars  in  the 
cooler  box. 

A  double  capacity  Coca-Cola  jar  can  be  furnished  in  place  of  two 
regular  jars.  This  double  capacity  jar  can  be  equipped  with  either  two 
syrup  pumps  or  one  syrup  pump  and  one  crushed  fruit  cover ;  permitting 
the  filling  of  the  jar  without  the  removal  of  the  pump. 

In  the  cooler  box  are  three  crushed  fruit  bowls  and  ladles.  These  are 
placed  between  the  storage  compartment  and  the  attemperating  chamber. 
In  place  of  two  of  these  crushed  fruits  a  double  capacity  jar  may  be  sup- 
plied at  no  additional  cost  which  can  be  used  as  a  whip  cream  container. 
A  milk  pump  may  be  substituted  for  all  three  jars  if  desired.  An  addi- 
tional charge  is  made  if  the  milk  pump  is  wanted. 

The  cooler  box  may  also  be  equipped  with  six  crushed  fruit  bowls  over 
the  attemperating  chamber  in  place  of  the  corrugated  drain  cover  which  is 
regularly  supplied.     If  the  crushed   fruits  are  desired,  there  will  be  an 


420 


CORK  INSULATION 


additional  charge.  All  of  ihese  crushed  fruit  jars  are  equipped  with  black 
insulating  hinged  covers  in  which  are  fitted  porcelain  name  plates.  Ladles 
are  supjilied  for  each  jar. 


■:w  OF  THE  rM\  i;rs.\i.  miv 

CORKBOARD    INSULATION. 


WICOLl),    SHOWING 


Iiisiilatioii. — It  IS  not  possible  to  build  a  perfectly  insulated  box.  The 
best  that  can  be  done  is  to  take  every  possible  jirecaution  against  permitting 
unnecessarv  losses  through  fauU\   insulation  or  construction. 


FIG.    208.— PURE  fORKI'.OARl)    INSl  LAT 


USKD   1!Y    MECHANICOLIX 


Pure  cork  board  is  the  best  insulator  known,  other  than  a  perfect 
vacuum  and  it  is  not  possible  to  obtain  a  vacuum  in  building  a  fountain. 
Therefore,  the  next  best  thing  is  used,  pure  cork  board  as  shown  in 
Fig.  208. 

A  minimum  thickness  of  three  inches  of  cork  is  used  in  front,  ends, 
bottom,  and  top,  and  there  are  five  inches  in  the  back.  This  3-inch  mini- 
mum of  pure  cork  board  is  supplemented  with  additional  ground  cork, 
which  fills  every  inch  of  space  in  the  interior  of  the  box  around  the  brine 
tank. 


REFRIGERATED  SODA  FOUNTAIN  421 

Insulated  Draft  Ann. — This  is  another  exclusive  Liquid  feature  that 
helps  to  produce  the  wonderful  results  certified  to  by  Prof.  Gebhardt  of 
The  Armour  Institute. 

Metal  is  a  thermal  conductor,  that  is,  it  conducts  heat  just  as  a  wire 
conducts  electricity.  An  uninsulated  metal  draft  arm  will  pick  up  heat 
from  room  temperature  and  raise  the  temperature  of  the  water  drawn 
from  the  coolers. 

The  Liquid  draft  is  made  of  stamped  nickel  silver,  silver  plated,  and  is 
filled  with  cork,  insulating  the  block  tin  tube  which  carries  the  water  from 
the  coolers  to  the  head  of  the  draft  arm. 

Aside  from  its  actual  value  in  conserving  refrigeration,  the  draft  is 
worth  while  by  reason  of  its  attractive  appearance. 

The  old  stereotyped  design  is  gotten  away  from  and  the  new  type 
outfit  adds  materially  to  the  appearance  of  the  fountain. 

There  is  also  provided  a  perfectly  sanitary  channel  for  the  flow  of 
soda  water  from  where  it  leaves  the  coolers  up  to  the  time  it  is  dispensed 
into  a  glass  for  service  to  a  customer. 

Block  tin  is  the  only  sanitary  metal  impervious  to  the  chemical  action 
of  soda  water  or  carbonic  gas. 

RUBBER 

MOULDED  COVER 


MOULDED 
INSULATING 
RING 


TUBULAR 
RUBBER  GASKET? 

FIG.    209.— SECTION   THROUGH    COVER   AND   LID,    SHOWING    CORKBOAKD 
INSULATION. 

Breaking  Metal  Co>ifacfs.—\leta\  is  a  thermal  conductor,  that  is,  it 
conducts  heat  or  cold.  Fig.  209  shows  how  all  metal  contacts  between 
the  top  cappings  nad  the  linings  are  broken. 

If  this  was  not  done  the  heat  from  the  room  temperature  would  be 
communicated  to  the  metal  capping  and  carried  into  the  box  through  con- 
tact with  the  metal  linings.  This  would  result  in  putting  an  unnecessary 
load  on  the  refrigerating  unit,  soft  ice  cream,  and  loss  through  shrinkage. 

Completely  Insulated  Syrup  Enclosure.— The  illustration  shows  some 
very  radical  changes  in  the  construction  of  the  Syrup  Enclosure,  all  made 
to  conserve  refrigeration. 

The  syrup  jars  are  completely  enclosed  and  the  enclosure  is  insulated 
with  slabs  of  pure  cork  board  at  front,  ends,  top  and  back. 

The  front  of  the  enclosure  is  faced  with  Bakelite  panels,  mahogany 
color,  which  add  to  the  appearance  and  afford  additional  insulation. 


422 


CORK  INSULATION 


The  bottom  lining  in  the  enclosure  is  contacted  with  the  walls  of  the 
brine  tank.  Metal  is  a  thermal  conductor,  i.e.,  heat  units  flow  through  it 
as  does  an  electric  current.  The  contact  between  the  walls  of  the  brine 
tanks,  with  their  zero  temperature,  and  the  tinned  copper  lining  of  the 
syrup  enclosure,  serves  to  carry  the  cold  to  this  enclosure. 


^  x^ 


FIG.   210.— SECTION   OF  CORKBOARD  INSULATED   SYRUP  ENCLOSURE. 

Metal  contacts  between  the  enclosure  linings  and  the  capping  around 
the  top  of  the  enclosure  are  broken  by  strips  of  non-conducting  material, 
so  that  this  capping  will  not  conduct  heat  into  the  enclosure.  See  also, 
in  description  of  Bakelite  pump  plate,  the  additional  precaution  exercised 
at  this  point. 


FIC.   2n.— CORK   INSULATED    COVER   RING. 


REFRIGERATED  SODA  FOUNTAIN 


^23 


424  CORK  INSULATION 

Covers  for  Junior  Box. — As  there  is  but  a  single  opening  on  the 
Junior  type  Mechanicold,  the  full  opening  cover  is  supplied  with  dou- 
ble point  hinges. 

These  lids  are  made  of  16-gauge  nickel  silver  (weighing  2^/4  pounds 
to  the  square  foot).  The  linings,  also  of  nickel  silver,  are  formed  so  as  to 
fit  inside  the  turned  down  edges  of  the  top.  This  is  known  as  telescoping 
and  the  joint  is  flooded  with  solder,  making  what  amounts  to  one  piece 
construction. 

Between  the  top  and  lining  is  insulation  of  pure  cork  board. 

The  double  point  hinge  permits  of  the  full  opening  of  the  lid. 

The  raised  edge  around  the  opening  in  the  capping  which  received  the 
lid,  is  die  stamped  and  will  not  break  down.  It  prevents  moisture  on  the 
cover  getting  into  the  ice  cream  can. 


CORK    INSULATION 

Appendix 


REFRIGERATION  IN  TRANSIT* 

By  Dr.  M.  E.  Penningtux. 

Chief,    Food    Research    T.ahoratory,    Bureau    of    Chemistry, 
United    States    Departnient    of    Agriculture. 

The  people  of  the  United  States  are  as  dependent  upon  refrig- 
erator cars  for  their  food  supply  as  are  the  people  of  England  up- 
on her  ships.  The  English  refrigerated  food  ship  is  the  result  of 
a  systematic  evolution;  the  American  refrigerator  car,  like  Topsy, 
has  "just  growed."  The  United  States  has  now  well  over  one 
hundred  thousand  refrigerator  cars  belonging  to  railroads.  It  costs 
at  least  $1,500.00  to  build  a  refrigerator  car,  and  most  of  them  are 
in  need  of  rebuilding  after  five  years  of  service.  With  such  an  in- 
vestment and  cost  of  maintenance,  and  with  the  responsibility  of 
transporting  fresh  food  to  the  people,  we  may  well  inquire  into 
the  efficiency  of  the  car  for  the  work  it  is  performing,  and  into  the 
expense   involved. 

The  United  States  Department  of  Agriculture,  through  the  Bur- 
eaus of  Plant  Industry  and  Chemistry,  has  for  some  years  been 
studying  the  temperatures  required  to  preserve  perishable  produce 
in  transit.  The  Department  has  obtained  definite  information  on 
fruits,  vegetables,  dressed  poultry  and  eggs.  It  is  now  determining 
the  most  efficient  and  economical  means  of  transporting  these  per- 
ishables. The  problem  is  of  great  importance  to  the  shippers,  to 
the   railroads,   and   to  the   consumer  as   well. 

The  efficiency  of  the  refrigerator  car  depends  upon  such  factors 
as  the  quantity  and  kind  of  insulation,  the  type  and  the  capacity 
of  the  ice  bunkers,  the  size  of  the  car,  the  temperature  of  the  en- 
tering load,  the  manner  of  stowing  the  packages,  the  circulation  of 
cold  air  from  the  ice  bunkers,  and  the  freedom  of  the  insulating  ma- 
terial from  moisture.  The  economy  of  operation  depends  on  such 
factors  as  the  weight  of  the  car  in  relation  to  the  weight  of  the 
load,  the  amount  of  ice  required  to  cool  the  product  in  transit  or 
to  maintain  the  initial  temperatures  of  the  precooled  load,  and  the 
length    of    life    of    the    car.      All    these,    and    other    questions    are    the 


'Address   before   the   Chicago   Traffic    Chib,    October    5th,    1916.       Reprint   from   the 
Waybill.   October,    1916.      N'olume   No.    7. 

425 


426  CORK  INSULATION 

subject  of  investigation  in  the  Department  of  Agriculture  in  con- 
nection with  the  study  of  the  preservation  of  the  good  condition 
of   perishables   vi^hile  in  transit. 

Apparatus  and  methods  of  investigation  had  to  be  developed 
to  obtain  the  necessary  data.  Gradually  there  has  been  evolved  an 
arrangement  of  electrical  thermometers  which  can  be  installed  not 
only  in  appropriate  locations  in  the  car,  but  within  the  packages, 
and  even  inside  an  orange,  peach,  chicken  or  fish.  The  wires  from 
these  thermometers  run  out  between  the  packings  of  the  door, 
and  the  terminals  are  permanently  or  temporarily  attached  to  the 
indicators  installed  in  an  accompanying  caboose. 

Fundamental   Facts  Established. 

To  complete  this  investigation  will  require  years  of  detailed 
study.  Certain  fundamental  facts,  however,  have  been  established 
and  are  outlined  in  this  paper.  For  example,  the  distribution  of 
the  cold  air  from  the  ice  bunker  throughout  the  car  is  vital  to  the 
preservation  of  the  lading.  The  circulation  of  the  air  is  produced 
and  maintained  by  the  difference  in  weight  of  warm  and  cold  air. 
The  actual  difTerence  between  the  weight  of  a  cubic  foot  of  air  at 
65°  F.  (1.18  oz.)  and  32°  F.  (1.27  oz.)  is  only  0.09  ozs.  Experi- 
ments with  stationary  precooling  plants,  cooled  by  ice  or  by  ice 
and  salt,  have  shown  that  the  best  and  most  economical  results 
are  obtained  by  hanging  a  basket  of  suitable  ice  capacity  close  to, 
but  actually  free  from  the  walls  of  the  room,  and  closing  off  the 
basket  by  an  insulated  bulkhead  open  about  twelve  inches,  both  at 
the  top  and  bottom,  to  permit  entrance  and  exit  of  air.  In  this 
way  a  large  surface  of  ice  is  exposed  to  air  contact  and  the  air  is 
compelled  to  travel  over  the  entire  column  of  ice  before  it  escapes. 
The  insulated  bulkhead  prevents  the  absorption  of  heat  from  the 
commodity  and  from  the  car,  varying  in  quantity  according  to  the 
distance  from  the  ice.  The  bulkhead  also  facilitates  a  steady  ascent 
and  progression  of  the  warm  air  in  the  car  toward  the  top  of  the 
bunker.  To  further  facilitate  the  distribution  of  cold  air  throughout 
the  space,  floor  racks  four  inches  high  have  been  installed. 

Now  let  us  see  what  practical  results  such  a  combination  pro- 
duces when  applied  to  a  refrigerator  car  which  is,  in  other  respects, 
of  the  usual  type.  Chart  I*  shows  the  average  temperature  in 
three  cars  of  oranges  in  the  same  train  in  transit  between  Los  An- 
geles and  New  York,  each  car  containing  462  boxes  of  fruit.  Car 
"A"  had  the  box  bunker  and  open  or  slatted  bulkhead  so  commonly 
seen  in  present  day  refrigerators.  The  lading  was  placed  directly  on 
the  floor.  Car  "B"  had  a  basket  bunker,  insulated  solid  bulkhead, 
and  a  rack  four  inches  off  floor.  Car  "C"  was  of  the  same  con- 
struction as  car  "B"  but  the  ice  was  mixed  with  nine  per  cent  salt 

•The  study  of  fruits  and  vegetables  is  being  conducted  by  the  Bureau  of  Plant 
Industry,  under  the  supervision  of  Mr.  H.  J.  Ramsey.  I  am  indebted  to  him  for  the 
data  on  oranges  and  also  such  other  facts  concerning  the  transportation  of  fruits 
and  vegetables  as  are  brought  out   in  this  paper. 


REFRIGERATION  IN  TRANSIT 


427 


CHART  I. 


the  first  day  and  five  per  cent  of  the  added  ice  on  the  second.  The 
temperature  of  the  load  in  the  car  "A"  averaged  54.4°  F.  The  tem- 
perature of  the  load  in  the  car  "B"  averaged  49.5°  F.,  while  car  "C,"  in 
which  salt  had  been  added  to  the  ice,  not  only  cooled  the  oranges 
more  quickly  but  reduced  the  average  temperature  of  the  load  to 
45.5°  F.,  a  gain  of  9°  F.  as  compared  with  car  "A."  The  amount  of 
ice  placed  in  the  bunkers  in  car  "A,"  including  that  remaining  in 
them  at  destination,  was  approximately  23,200  pounds.  In  car  "B" 
the  ice  amounted  to  18,675  pounds,  a  saving  of  more  than  two  tons. 
Car  "C,"  which  had  been  salted,  had  22,750  pounds  of  ice,  still  a 
little  less  than  car  "A." 

The  results  obtained  with  car  "C"  open  up  great  possibilities 
in  the  better  distribution  of  such  extremely  perishable  products  as 
strawberries,  raspberries  and  cherries,  widely  produced  under  con- 
ditions which  generally  preclude  proper  precooling  before  loading 
into  the  car.     The  insulated  bulkhead   prevented  the  frosting  of  the 


428  CORK  INSULATION 

lading  next  to  the  bunker,  and  the  floor  rack  provided  a  quick  run- 
way for  the  very  cold  air,  which  soon  lost  its  temperature  of  20°  F., 
or  even  less,  by  the  absorption  of  the  heat  of  the  lading  and  of  the 
car. 

Such  results  with  the  basket  bunker,  insulated  bulkhead  and  floor 
rack,  combined,  naturally  raise  the  question  of  the  relative  value  of 
each  of  the  three  factors  in  producing  and  maintaining  circulation, 
and  gaining  the  available  refrigeration  from  the  ice.  Experimentation 
shows  that  a  rack  on  the  floor  of  the  car  hastens  the  cooling  of  the 
load,  and  affords  very  decided  protection  to  the  lower  layer  of  goods 
against  both  frost  and  heat.  The  floor  rack,  alone,  however,  is  far 
less  efficient  than  the  combination  of  the  basket  bunker  and  insulated 
bulkhead  with  the  floor  rack.  The  addition  of  insulation  to  bulkhead 
increases  circulation  and  the  lading  is  more  rapidly  and  completely 
cooled  than  when  the  bulkhead  is  either  not  insulated  or  is  open. 
For  example.  Chart  II  shows  two  cars  of  similar  size  and  construc- 
tion, one  of  which  was  provided  with  a  floor  rack  and  an  insulated 
bulkhead,  the  other  as  commonly  used.  Both  were  loaded  with  eggs. 
The  car  with  the  insulated  bulkhead  and  the  floor  rack  reduced  the 
average  temperature  of  the  load  17°  F.  in  sixty-four  hours.  The  load 
in  the  ordinary  car  showed  a  reduction  of  7.5°  F.  during  the  same 
period.  The  average  temperature  of  the  car  with  the  insulated  bulk- 
head and  the  floor  racks  was  5.5°  F.  lower  than  the  ordinary  car. 
That  it  is  not  advisable  to  cease  improvements  with  the  floor  rack 
and  the  insulated  bulkhead  is  indicated  by  experiments  which  show 
that  quick  cooling  by  ice  and  salt  safely  performed  with  basket  in- 
sulated bulkhead  and  floor  rack  is  not  possible  without  it.  The 
pocketed  cold  air  at  the  box  bunker,  which  is  always  observed  with 
bunkers  of  the  box  type,  causes  frosting  of  the  goods  against  the 
bulkhead  even  when  that  is  insulated. 

The  failure  of  refrigerator  cars  to  maintain  even  temperatures 
throughout  the  load  has  been  a  serious  menace  to  extremely  perish- 
able products.  In  order  to  produce  temperatures  at  the  top  of  the 
load  between  the  doors — commonly  the  warmest  place  in  the  car — 
low  enough  to  carry  dressed  poultry  safely,  it  has  been  necessary  to 
freeze  the  birds  at  the  bunker.  While  freezing  in  transit  does  not 
injure  the  food  value  of  dressed  poultry,  it  does  lower  its  money 
value  at  certain  seasons  or  in  some  markets.  Better  air  circulation 
tends  to  equalize  temperatures,  as  shown  in  Chart  III.  In  the  car 
with  the  box  bunkers  and  open  bulkhead  (car  B),  where  the  load 
was  placed  on  floor  strips,  the  package  at  the  bunker  on  the  floor 
froze  solidly  (23°  F.)  during  a  four-day  haul,  although  the  package 
on  the  top  of  the  four  foot  load  was  35.4°  F.  A  similar  car  (car  A), 
except  that  it  had  a  basket  bunker  with  insulated  bulkliead  and  a 
floor  rack,  maintained  an  average  tcm])eraturc  of  29.3°  F.  at  the 
bunker  and  34.1°  F.  in  the  package  on  the  top  of  the  load  between 
the    doors.     In    the    one    case,    the    average    difference    between    the 


REFRIGERATION  IN  TRANSIT 


429 


430  CORK  INSULATION 

warmest  and  the  coldest  points  in  the  car  was  12.3°  F.,  in  the  other 
4.8°  F. 

The  reduction  of  the  temperature  on  top  layers  can  be  increased 
by  better  and  more  judiciously  applied  insulation,  especially  in  the 
roof  of  the  car.  Most  of  the  cars  in  service  have  the  same  amount  of 
insulation  throughout,  regardless  of  the  additional  strain  on  the  roof 
during  the  heat  of  summer,  and  on  the  floor  when  frost  protection' 
is  necessary.  Experiments  are  now  under  way  to  determine  just 
how  much  insulation  it  is  advisable  to  have  in  roof  and  floors  as 
well  as  in  the  body  of  the  car.  At  present  the  work  indicates  that 
there  is  scarcely  a  refrigerator  in  the  country  which  is  sufficiently 
well  insulated  to  be  an  economical  as  well  as  a  safe  carrier  of  perish- 
ables. A  large  proportion  of  the  refrigerator  cars  now  in  service  have 
one  inch  of  insulating  material  over  the  entire  car.  Some  have  two 
inches  throughout,  and  a  few,  comparatively,  have  had  special  care 
bestowed  on  the  insulation  of  the  roof  and  the  floor.  The  lack  of 
sufficient  insulation,  especially  on  the  roof  of  the  car,  has  been 
responsible  for  the  fact  that  the  top  layers  of  such  fruits  as  peaches, 
strawberries  and  cherries  are  so  different  in  quality  from  the  rest  of 
the  carload  that  they  must  be  sold  as  separate  lots.  The  higher 
temperature  of  the  upper  half  of  the  car  has  led  the  shippers  to  urge 
longer  cars,  that  they  might  extend  rather  than  heighten  the  stacks 
of  packages.  As  a  result  of  this,  and  also  in  line  with  a  general 
increasing  of  capacity  of  all  cars,  the  refrigerator  has  been  lengthened 
regardless  of  the  fact  that  heat  transmission  increases  directly  as 
the  number  of  square  feet  of  surface  enclosing  the  car  space.  For 
example,  a  car  whose  roof,  walls  and  ends  aggregate  1170  square 
feet  and  which  is  33  feet  between  linings,  has  the  same  amount  of 
temperature  protection  with  two  inches  of  insulation  as  a  car  with 
2.5  inches  of  insulation  whose  surfaces  aggregate  1407.5  square  feet, 
and  whose  length  between  lining  is  40  feet  6  inches. 

To  determine  the  economical  size  of  a  refrigerator  car  in  rela- 
tion to  the  height  of  the  lading,  the  consumption  of  ice,  the  total 
weight  of  the  car  and  its  initial  cost,  is  an  economic  problem  of  im- 
portance.    Studies  to  obtain  such  information  are  now  in  progress. 

The  most  obvious  results  due  to  increased  insulation  are,  first 
better  protection  to  the  lading  against  both  heat  and  cold,  and 
second,  a  saving  in  the  use  of  ice.  The  modern  trend  in  the  han- 
dling of  perishables  is  to  include  precooling  as  a  preparation  for 
shipment,  and  it  is  a  highly  desirable  practice  from  all  viewpoints. 

When  the  goods  enter  the  car  at  a  temperature  conducive  to 
preservation,  it  is  the  business  of  the  car  to  maintain  that  tempera- 
ture. The  goods  need  no  further  refrigeration,  and  the  ice  in  the 
bunkers  is  required  only  to  overcome  the  heat  leakage  through  the 
walls.  The  difference  in  performance  of  a  car  with  one  inch  of  insu- 
lation as  compared  with  a  similar  car,  except  that  the  latter  was  pro- 
vided with  two  inches,  is  shown  in  Charts  IV  and  V.  Both  cars  were 
loaded  with  eggs  and  closed  without  patting  any  ice  in  the  bunkers. 


I 


REFRIGERATION  IN  TRANSIT 


431 


432 


CORK  INSULATION 


CHART  IV 


The  weather  at  the  loading  point  was  cool  enough  to  ensure  a  cool 
car.  The  possible  dangers — against  which  the  insulation  was  to 
protect — lay  ahead.  Chart  IV,  showing  the  performance  of  the  car 
with  one  inch  of  insulation,  indicates  very  plainly  that  it  could  not 
protect  the  eggs.  Chart  V,  on  the  other  hand,  shows  that  two  inches 
of  insulation,  even  with  higher  atmospheric  temperatures,  delivered 
the  eggs  at  destination  at  practically  the  same  temperature  as  they 
entered  the  car,  and  the  maximum  variation  was  but  four  degrees. 

The  one  inch  car  needed  10,000  pounds  of  ice — the  two  inch  car 
needed  none.  Is  it  any  wonder  that  wide-awake  shippers  are  picking 
out  their  refrigerator  cars  more  and  more  carefully? 

Experimentation  indicates  that  marked  economies  can  be   effected 


REFRIGERATION  IN  TRANSIT 


433 


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ill  the  consumption  of  ice  in  transit  aside  from  the  question  ot  insu 
lalion.  Raising  the  load  ofif  the  floor,  inducing  a  circulation  of  air 
in  the  car,  and  bringing  a  large  surface  of  ice  into  contact  with  the 
air,  tends  to  reduce  the  amount  of  ice  used.  As  stated  in  another  con- 
nection in  this  paper,  a  carload  of  oranges  in  a  car  having  box 
bunkers  with  open  bulkheads,  and  without  a  rack  on  the  floor,  had 
23,200  pounds  of  ice  put  into  the  bunkers  between  Los  Angeles  and 
New  York.  A  similar  car  provided  with  basket  bunkers,  insulated 
bulkheads,  and  a  floor  rack,  had  18,675  pounds.  Neither  load  was 
precooled. 


434 


CORK  INSULATION 


That  precooling  of  the  lading  means  fewer  icings  in  transit  is 
a  matter  of  common  knowledge.  That  hard  freezing  of  the  goods, 
whereby  they  not  only  do  not  require  additional  chilling  in  transit, 
but  actually  furnish  refrigeration  to  the  car,  is  not  so  commonly 
recognized.  Chart  VI  shows  the  temperatures  in  transit  of  20,000 
pounds  of  poultry  which  went  into  the  car  at  0°  F.  The  railroad 
icing  record  shows  that  4,700  pounds  of  ice  was  added  during  the 
eight-day  haul,  and  470  pounds  of  salt.  Other  experiments,  under 
comparable  conditions,  show  that  nearly  5,000  pounds  of  ice  is  used 
by  cars  carrying  20,000  pounds  of  poultry  chilled  to  30-32"  F.  during 
a  four-day  haul,  or  approximately  twice  as  much. 

The  temperature  records  show  that  the  poultry  grew  gradually 
warmer,  faster  on  the  top  and  bottom  of  the  load,  where  the  heat 
leakage  from  the  roof  and  floor  was  most  pronounced,  and  most 
slowlv  in  the   center  of  the  load,  where  the   packages  protected  one 


REFRIGERATOR  CARS  435 

another.  The  chart  also  shows  that  the  amount  of  salt  added  during 
transit  is  insufficient  to  maintain  the  temperature  produced  on  the 
initial  salting,  when  the  full  ten  per  cent  of  the  weight  of  the  ice 
was  present.  It  must  be  remembered  that  the  salt  bores  through  the 
ice  and  escapes  as  brine  more  rapidly  than  the  bulk  of  the  ice  melts, 
hence  it  is  in  constantly  decreasing  proportion.  Icing  and  salting 
rules  take  no  account  of  the  fact.  It  is  quite  obvious  that  different 
rules  must  be  formulated  if  efficiency  is  to  be  secured. 

This  problem,  like  all  the  other  problems  confronting  the  shipper 
and  the  carrier  who  are  engaged  in  getting  perishables  to  market  in 
good  condition,  can  be  solved  only  on  the  basis  of  exact  knowledge. 
That  knowledge  the  United  States  Department  of  Agriculture,  in  co- 
operation with  the  shippers  and  the  railroads,  is  now  endeavoring  to 
acquire  and  to  pass  on  to  all  whom  it  may  benefit. 


THE  ABILITY  OF  REFRIGERATOR  CARS  TO  CARRY 
PERISHABLE  PRODUCTS.* 

By  Dr.  M.  E.  Pennington. 

Chief,  Food  Research  Laboratory,  United   States  Department  of  Agriculture, 

Bureau   of   Chemistry,   Philadelphia,   Pa. 

Mr.  Herman  J.  Pfeifer  (Terminal  R.  R.  Ass'n,  St.  Louis):  Mr. 
President,  ladies  and  gentlemen:  At  our  last  meeting,  Mr.  Aishton, 
President  of  the  Chicago  &  Northwestern  Railroad,  made  the  remark 
that  on  the  advice  of  Dr.  Pennington,  his  road  appropriated  the  sum 
of  $200,000  for  improvements  in  the  matter  of  refrigerator  cars  in  a 
shorter  time  than  an  equal  sum  of  money  had  ever  been  appropriated 
by  that  railroad. 

The  question  of  food  conservation  is  intimately  connected  with 
its  transportation,  and  a  great  deal  of  our  food  being  of  a  perishable 
nature,  which  must  be  transported  in  refrigerator  cars,  makes  the 
consideration  of  this  subject  a  very  vital  one  at  this  time.  The  sub- 
ject, therefore,  about  which  Dr.  Pennington  is  to  speak,  namely,  the 
ability  of  refrigerator  cars  to  transport  perishable  products  safely, 
is   one   of   vital    interest,   under   present   conditions. 

Dr.  Pennington  is  recognized  throughout  the  country  as  an 
authority  on  food  conservation  and  preservation,  and  it  now  gives 
me  great  pleasure  to  introduce  to  you  Dr.  M.  E.  Pennington,  Chief 
of  the  Food  Research  Laboratory  of  the  United  States  Department 
of  Agriculture.      (Applause.) 

•Reprint  from  the  Official  Proceedings,  St.  Louis  Railway  Club,  October  12th, 
1917,  Vol.  22,  No.  6.  Address  delivered  before  the  St.  Louis  Railway  Club, 
October    12th,    1917. 


436 


CORK  INSULATION 


Mr.  President,  Members  and  Guests  of  the  St.  Louis  Raihvay  Club: 

It  is  with  a  great  deal  of  embarrassment  that  I  undertake  to 
address  you  railroad  men  upon  a  subject  dealing  with  facts  with 
which  so  many  of  you  are  already  well  acquainted. 


TYPC    I 
BOX    aUNKCK.     OPCN    BULKMCAO, 

PCRMANCNT    rcOOfl    iTDIPS. 
INSULATION  BPOMCIf  Br  AIR  iPACCS 


>i  imuLATION 


V.9.  0£fT  or  ASRICULTUHC 


FIG.   I. 

The  responsibility  of  appearing  before  you  is  great,  dealing,  as  I 
shall,  with  matters  which  are  of  daily  occurrence  in  your  own  line 
of  business,  and  inasmuch  as  I  come  here,  talking  to  you  in  your  own 
bailiwick,  the  only  excuse  that  I  can  plead  is  that  we  are  at  war, 
that  we  need  food,  and  that  food  must  be  saved.  Anything  that  we 
can  do  to  save  the  chicken,  the  tg%,  the  fish,  no  matter  to  how  small 
an  extent,  we  must  do,  as  a  part  of  the  work  that  we  all  have  in 
hand,  to  the  end  that  we  may  win  this  war. 


i 


REFRIGERATOR  CARS 


437 


If  I  can  do  just  a  very  little  bit  by  placing  before  you  some  of 
the  results  of  the  investigations  of  the  Department  of  Agriculture  in 
the  matter  of  saving  foodstuffs,  I  will  be  more  than  glad,  and  I 
know  that  you,  as  patriotic  American  citizens,  will  rejoice,  also. 


i 


RErRIGERATOR     CAR 
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BASKCT     eU/VKCff.      INiULArCD 

BULKMCAD,      FlOO"    fTACrS 

MAiS£D       INSULATIOM 


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V 

TKANSn 

INVCSTIGATI0N5 

U S    DCPT 

cr  Arsaico 

lturc 

We  are  being  daily  more  and  more  impressed  with  the  evidence 
to  show  that  this  war  will  be  won  by  food. 

The  task  of  feeding  the  Allies  and  ourselves  becomes  more  im- 
portant as  it  becomes  more  difficult.  The  President  urges  increased 
production  and  agriculture  is  fostered  as  never  before — yet  we  know 
that  the  calling  of  men  to  the  colors  and  to  the  many  activities  of 
war  means  greater  and  greater  difficulty  in  the  production  of  the 
foodstuffs    necessary    to    win    the    war.      Therefore,    conservation    and. 


438  CORK  INSULATION 

the    elimination    of    food    waste    and    spoilage    has    become    a    world 
question  of  vital  interest. 

The  question  of  transportation  has  also  become  of  overwhelming 
importance.  Our  railroads  are  taxed  to  their  utmost,  and,  as  in  the 
food  question,  the  future  seems  to  hold  problems  even  harder  to 
solve  than  those  now  at  hand.  Every  rail,  locomotive  and  car  must 
be  utilized  for  maximum  service.  The  refrigerator  car,  especially, 
becomes  an  object  of  renewed  interest,  because  upon  it  depends 
very  largely  our  ability  to  render  available  the  crops  produced  and 
food  animals  raised.  It  must  carry  a  full  load,  yet  we  must  not,  in 
our  zeal  to  transport  perishables,  permit  any  spoilage  or  damage  in 
transit  that  can  possibly  be  avoided. 

The  investigation  of  the  transportation  of  perishables  which  is 
now  under  way  in  the  United  States  Department  of  Agriculture  has 
shown  that  the  refrigerator  equipment  on  the  various  lines  differs 
widely  in  ability  to  protect  against  heat  and  cold.  This  variation 
depends  to  a  certain  extent  upon  the  size  and  character  of  the  load 
as  well  as  upon  the  construction  of  the  car.  It  is  my  purpose  to 
discuss  with  you  some  of  the  results  of  these  investigations,  com- 
paring the  performance  of  cars  of  varying  types  when  loaded  with 
varying  quantities  of  the  commodity  to  be  transported.  First,  how- 
ever, let  me  very  briefly  outline  the  major  dififerences  in  the  con- 
struction of  the  cars  used  in  these  experiments.  In  the  general  pur- 
pose refrigerator  car  we  find  two  types  of  bunker — one  known  as  the 
"box  bunker,"  illustrated  in  Fig.  I,  in  whhich  the  ice  rests  directly 
against  the  end  and  sides  of  the  car — and  the  other,  known  as  the 
"basket  bunker"  in  which  the  ice  is  held  in  a  wire  container  two 
inches  away  from  walls  and  bulkhead  (see  Fig.  II).  The  box  bunker 
usually  has  an  open  bulkhead  of  wood  or  metal.  Sometimes  we  find 
a  solid  wooden  partition  open  at  top  and  bottom.  The  basket 
bunker  commonly  has  a  solid,  wooden  bulkhead,  open  twelve  inches 
at  the  bottom  and  fourteen  inches  at  the  top,  and  in  the  new  cars 
this  bulkhead  is  insulated  with  one  inch  of  a  recognized  insulator. 
The  new  cars,  also,  have  a  rack,  on  the  floor,  four  inches  in  the  clear, 
made  of  2x4  runners  and  1x3  cross  slats,  lJ/2  inches  apart.  These 
racks  are  fastened  to  the  sides  of  the  car  with  hinged  bolts.  They 
are  divided  in  the  middle  so  that  they  can  be  turned  up  against  the 
walls  when  the  car  is  cleaned.  They  are  absolutely  necessary  for 
the  safe  carrying  of  perishable  loads.  Most  of  the  cars  now  on  the 
lines  are  without  racks.  Some  have  permanent  strips  on  the  floors 
one  or  one  and  one-half  inches  in  height.  These  strips  are  practically 
valueless.  The  insulation  varies  from  a  few  layers  of  paper  to  three 
inches  of  some  recognized  insulator.  In  some  cars  the  layers  of 
insulation  are  broken  by  spaces — in  others  the  insulation  is  massed. 
The  cars  in  the  experiments  were  from  approximately  twenty-nine 
feet  between  bulkheads  to  approximately  thirty-three  feet. 

The  majority  of  the  experiments  used  as  illustrations  are  taken 
from   the   investigations   on    the   transportation   of   eggs,   because   that 


REFRIGERATOR  CARS 


439 


;         TenPef>AT</n£     m.TtfANSIT    ej(P£/ilMCfiT-5334(SuMMARY) 

Floha.Ill.  TO  New  Yodfr.HY  ' 


.  PACKAOC.THC/tHOMCrenS 


OAD.  BCTWCCM  OOORiCtffTCIt 


CHART  VII. 


field  of  work  is  under  my  charge.  Whenever  the  shipment  of  fruits 
or  vegetables  is  used  to  emphasize  a  fundamental,  the  facts  have 
been  furnished  me  by  Mr.  H.  J.  Ramsey,  of  the  Bureau  of  Plant 
Industry,  under  whose  direction  all  such  commodities  are  being  in- 
vestigated. Of  course,  all  temperatures  were  taken  by  means  of 
electrical  thermometers  inserted  when  the  cars  were  loaded,  and 
the  mechanism  was  such  that  neither  the  doors  nor  the  hatches  were 
opened  to  take  records  nor  was  the  car  modified  in  any  way. 


440 


CORK  INSULATION 


Now  let  me  proceed  to  the  work  done  by  such  classes  of  cars 
as  above  indicated. 

The  car  factors  which  determine  the  size  of  the  load  which  can 
be  safely  carried  are  insulation,  bunkers  and  floor  racks.     Each  exer- 




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CHART    \TII. 

cises  a  specific  influence  as  indicated  in  Chart  VII.  This  experiment 
consisted  of  three  cars  which  had  been  in  experimental  service  for 
about  ten  months.  As  shown  on  the  chart,  cars  A  and  C  were  pro- 
vided with  basket  bunkers  and  floor  racks;  car  B  had  a  box  bunker 
and  strips  on  the  floor.     Cars  A  and  B  had  three  inches  of  insulation 


A 


REFRIGERATOR  CARS 


441 


in  the  roof,  two  inches  in  side  walls  and  ends  and  two  inches  of 
cork  in  the  floor.  Car  C  had  one  and  one-half  inches  in  the  walls 
and  two  inches  in  the  roof  and  floor.  Each  was  loaded  with  six 
hundred   cases   of  eggs   consolidated   from  pickup   cars,  and   each   re- 


CriART  IX. 

ceived  the  same  amount  of  ice  accurately  weighed  into  the  bunkers. 
About  twelve  thermometers  were  put  into  each  car.  For  our  pur- 
poses the  temperatures  in  the  cases  of  eggs  on  the  bottom  and  top 
of  the  load  are  especially  significant,  and  indicate  very  plainly  the 
amount  of  work  which  the  car  can  do.     For  example,  the  temperature 


442 


CORK  INSULATION 


of  the  eggs  on  the  floor  of  car  B,  between  the  doors,  was  66.5°  F. 
on  arrival;  car  C,  in  the  same  location,  was  45.5°  F.  and  car  A, 
44.5°  F.  The  packages  between  the  doors  on  the  top  of  the  load — 
in  this  case  five  layers  high — showed  for  car  B,  64°,  for  car  C,  56.5°, 
and  for  car  A,  55.5°   F. 

The  behavior  of  the  packages  on  the  floor  of  car  B  between  the 
doors  is  especially  noteworthy.  They  were  continuously  higher  in 
temperature   than   the   packages   on   the   top   of   the   load,   a   condition 


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quite  contrary  to  the  generally  held  idea  that  the  coolest  place  in  a 
refrigerator  car  is  its  floor.  That  is  only  true  when  the  construction 
is  such  that  the  cold  air  from  the  bunkers  can  travel  along  the  car 
floor.  This  experiment,  and  many  others  that  we  have  made,  shows 
conclusively  that  a  rack  4  inches  above  the  floor  is  necessary  if  the 
goods  on  the  bottom  of  the  load  in  the  two  middle  quarters  of  the 
car  are   to  be   refrigerated.      It   is   of   interest   to   note,   also,   that  the 


REFRIGERATOR  CARS 


443 


insulation  in  cars  A  and  B  is  unusually  heavy,  in  fact,  more  than 
twice  as  much  as  in  most  of  the  refrigerator  cars  now  in  service, 
yet,  because  of  the  construction  of  the  bunkers  in  car  B  and  the 
absence  of  a  rack  on  the  floor,  there  was  practically  no  refrigeration 
except  near  the  bulkheads. 

Manifestly,  car  B  is  not  a  satisfactory  carrier  for  a  heavy  load 
of  eggs.  Car  A,  on  the  other  hand,  has  done  its  work  well,  and  at 
first  sight  car  C,  having  less  insulation,  appears  to  be  efficient  for  a 


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load  of  600  cases  of  eggs  during  hot  summer  weather.  Further  study, 
however,  shows  that  the  packages  around  the  walls  of  car  C  came 
into  destination  over  6°  higher  than  the  corresponding  packages  in 
car  A  (Chart  VIII),  though  when  loaded  they  were  but  3°  apart. 

Car  C  used  about  1,000  pounds  more  ice  than  car  A  and,  on  the 
whole,  did  less  satisfactory  work,  especially  around  the  walls,  where 
actual  deterioration  due  to  heat  undoubtedly  occurred. 


444 


CORK  INSULATION 


It  may  be  said  that  in  the  experiment  cited,  car  B,  having  the 
box  bunker  and  open  bulkhead,  was  unfairly  treated  in  that  the 
temperature  of  the  entering  load  was  distinctly  higher.  The  facts 
illustrated  in  Chart  IX  tend  to  nullify  the  significance  of  such  an 
argument.      In    this    experiment,   the    cars    had   two   inches   of   insula- 


c  ITART  Xll. 


tion  throughout,  but  car  A  was  of  the  box  bunker  type,  while  car  B 
had  a  basket  bunker  and  its  adjuncts.  Here  the  eggs  entering  car  A 
were  cooled  to  between  50  and  60°  F.,  while  those  in  car  B  ranged 
between  55  and  65°  F.  However,  car  A  could  not  even  maintain  the 
initial  temperature.  At  destination  the  packages  in  the  middle  of  the 
car  on  the  floor  were  nearly  5°  warmer  than  when  they  entered  the  car  and 


REFRIGERATOR  CARS  445 

those  in  the  top  layer  were  over  2°  higher.  Car  B,  on  the  contrary, 
brought  in  the  load  from  6  to  14°  lower  than  car  A.  These  two  cars 
were  loaded  with  600  cases  of  eggs  and,  so  long  as  the  atmospheric 
temperatures  were  above  80°  F.,  refrigeration  was  of  doubtful  efifi- 
ciency.  The  third  and  fourth  days  of  the  trip  were  unseasonably 
cool  and  also  rainy,  which  compensated  for  the  lack  of  insulation  in 
the  roof  and  permitted  the  load  in  the  car  B  to  drop  below  55°  F. 
before  the  end  of  the  fourth  day. 

The  performance  of  a  poorly  built  car,  said  to  contain  an  inch 
and  a  half  of  insulation  throughout,  as  compared  with  a  well  built 
car  known  to  have  one  and  a  half  inches  of  insulation,  is  well  illus- 
trated in  Charts  X  and  XI,  where  cantaloupes  were  hauled  for 
eleven  days  across  a  hot  territory.  The  top  layer  in  car  A,  loaded 
six  wide  and  four  high  at  the  bunkers,  was  in  such  bad  condition  on 
arrival  that  claims  were  filed  for  damage  in  transit.  Car  B,  on  the 
other  hand,  was  in  good  condition,  although  the  load  was  seven  cases 
wide  and  four  cases  high.  In  car  A  the  combination  of  a  lack  of 
cold  air  circulation  and  of  insulation  proved  disastrous,  even  though 
the  load  was  light  and  open  in  character,  and  much  easier  to  refrig- 
erate than  a  load  of  eggs.  In  fact,  we  know  that  eggs  can  not  be 
safely  loaded  more  than  three  layers  high  in  summer  weather  in 
cars  having  one  inch  of  insulation.  Cars  having  one  and  one-half 
inches  of  insulation,  if  provided  with  a  basket  bunker  and  a  floor 
rack,  can  carry  four  layers.  To  load  five  high,  we  must  have  three 
inches  in  the  roof  and  two  inches  in  the  walls,  ends  and  floors,  and 
good  air  circulation.  Beyond  five  layers  of  egg  cases  we  have  not 
succeeded  in  getting  good  refrigeration. 

This  is  illustrated  in  Chart  XII,  showing  top  and  bottom  layer 
temperatures  in  two  cars  stowed  six  layers  high,  making  700  cases 
to  the  load.  Car  A  is  of  the  same  type  as  was  used  in  Chart  VII,  where 
with  600  cases  it  did  good  work.  With  700  cases  there  was  practi- 
cally no  refrigeration  except  in  the  bottom  layer.  The  companion 
car,  B,  with  the  same  insulation  but  having  a  box  bunker,  did  not 
even  refrigerate  the  lower  layers.  The  packages  on  the  floor,  middle 
of  the  car,  were  often  warmer  than  the  top  of  the  load,  which  was 
only  12  inches  from  the  ceiling.  It  varied  more  than  5°  with  the 
daily  rise  and  fall  of  the  atmosphere  and  arrived  at  destination 
showing  an  increase  of  7.5°. 

Encouragingly  good  results  have  been  obtained  in  refrigerating 
heavy  loads  of  fruit  in  the  basket  bunker  cars  by  adding  salt  to  the 
ice  in  the  bunkers.  On  a  long  haul  across  a  hot  territory  salt  has 
been  added  to  the  ice  at  the  first  three  icing  stations.  By  that  time 
(the  third  day)  the  load  was  cooled  and  very  frequently  no  more  ice 
was  needed,  even  though  the  haul  continued  for  five  to  eight  days. 
The  air  issuing  from  the  bunkers  is  far  below  32°  F.,  but  the  circula- 
tion is  so  rapid  that  there  is  no  pocketing  at  the  bulkhead.  The  in- 
sulated   bulkhead    also    protects    the    load    so    that    frosting    does    not 


446 


CORK  INSULATION 


occur.  Salting  ice  in  a  box  bunker,  open  bulkhead,  merely  freezes  the 
load  next  to  the  bulkhead.  The  packages  in  the  middle  of  the  car 
are  not  benefited  because  of  a  lack  of  air  circulation. 

We  have  used  salt  to  assist  in  refrigerating  heavy  loads  of  eggs 
and  with  some   success,  but   we   have   not   succeeded   in   refrigerating 


(HART  Xll 


700  cases  in  a  car  33  feet  between  bulkheads.  The  records  of  car  A, 
in  Chart  XII,  bring  out  this  fact.  Three  per  cent  of  salt  was  added 
after  the  load  had  been  placed  in  this  car  and  salt  was  again  put  into 
the  bunkers  at  three  icing  stations.  While  the  car  was  not  able  to 
handle  so  heavy  a  load  during  the  very  hot  weather  prevailing,  it 
nevertheless  did  rather  remarkable  work  and  furnished  valuable  in- 
formation on  which  to  develop  a  more  economical  and  efficient   icing 


I 


REFRIGERATOR  CARS 


447 


system.  Car  A,  which  brought  the  sixth  layer  of  eggs  from  85° 
down  to  66.5°  F.,  used  12,660  pounds  of  ice  and  540  pounds  of  salt; 
car  B,  which  did  not  refrigerate  either  the  top  or  bottom  of  the 
middle  part  of  the  load,  used   19,755  pounds  of  ice. 

A  great  many  experiments  have  been  made  with  fruits  and  eggs, 


CHART  XI\', 


all  of  which  confirm  the  foregoing;  namely,  that  a  suitable  use  of 
salt  saves  ice  on  a  long  haul  and  greatly  increases  the  efficiency  of 
the  work  done   on  both  short  and  long  hauls. 

The  experiment  recorded  in  Chart  XIII  adds  still  further  to  our 
knowledge  of  car  construction  and  car  performance  when  salt  is  used 
with  the  ice.     In  this  case  we  had  short  cars,  so  that  by  comparison 


448  CORK  INSULATION 

the  two  inches  of  insulation  became  nearly  2.5  inches,  and  the  air 
circulation  was  more  rapid  because  of  lessened  distance.  Car  B  was 
of  the  usual  box  type;  car  A  had  a  box  bunker  with  an  insulated 
bulkhead  and  a  floor  rack;  car  C  was  of  the  standard  basket  type. 
Cars  A  and  C  received  salt  on  the  initial  icing.  They  were  neither 
iced  nor  salted  in  transit  on  an  88-hour  haul.  Car  B  was  iced  once. 
All  contained  from  400  to  500  cases  of  eggs.  The  three  lower  layers 
were  seven  cases  wide,  spaced  for  air  circulation,  and  the  upper 
layers  were  eight  cases  across.  The  average  of  all  the  thermometers 
in  the  packages  in  various  parts  of  car  B  showed  that  it  was  far 
above  cars  A  and  C  until  the  last  day  of  the  trip.  An  analysis  of 
temperatures  in  different  locations  shows,  further,  that  the  floor  of 
car  B  paralleled  the  top  layer  of  car  C.  Car  C  did  much  the  best 
work  of  the  three.  Car  A,  having  the  rack  and  the  insulated  bulk- 
head, but  not  the  basket  bunker,  did  not  succeed  in  maintaining  a 
sufficiently  rapid  air  circulation  to  cool  the  top  layer  more  than  5°. 
The  packages  on  the  floor,  on  the  contrary,  were  exaggeratedly 
chilled  because  of  the  pocketing  of  the  cold  air.  The  conclusion 
follows  that  even  with  an  openly  stowed  load,  the  car  must  be  pro- 
vided with  a  basket  bunker,  an  insulated  bulkhead,  a  floor  rack  and 
ample  insulation,  if  our  present  loads  are  to  be  materially  increased 
with  safety  to  the  commodity. 

Car  C  (Chart  XIV)  of  the  foregoing  experiment,  was  again 
used  with  a  load  of  about  600  cases,  stowed  eight  across.  The  ice 
was  salted  at  the  start  and  40  pounds  was  added  on  the  second  day. 
Thermometers  in  the  first,  fourth,  fifth  and  sixth  layer  packages  give 
an  instructive  picture  of  the  rise  in  temperature  with  the  height  of 
the  load.  Without  salt,  the  fourth  layer  would  be  the  stopping 
point.  The  fifth  layer  cases  around  the  walls  of  the  car  would 
suffer  if  the  weather  were  hot,  if  salt  were  not  used.  With  the  salt, 
as  this  experiment  shows,  we  can  load  five  high  with  impunity,  but 
not  six,  because  of  damage  to  wall  cases.  A  study  of  the  chart  shows 
that  the  40  pounds  of  salt  added  at  the  first  icing  station  was 
enough  to  cause  a  drop  in  temperature  in  all  except  the  sixth  layer 
wall  packages.  Had  another  charge  of  40  pounds  been  added  the 
next  day,  the  rise  shown  in  the  lower  layers  would  have  been  avoided 
and  the  fourth  and  fifth  layers  would  have  continued  to  cool  instead 
of  remaining  practically  stationary. 

The  investigation  has  convinced  us  that  in  the  future  ice  and 
salt  will  be  used  for  more  commodities  than  fresh  meats,  poultry 
and  fish.  Indeed,  it  is  the  only  way  that  we  now  see  by  which  very 
perishable  small  fruits  can  be  transported  in  good  condition  through- 
out the  entire  car.  Of  course,  a  definite  routine  for  its  application 
must  be  worked  out.  The  experiments  for  the  summer  just  ending 
have  yielded  much  information.  We  hope  that  by  the  end  of  another 
summer  we  can  bring  you  specific  instructions  for  a  number  of 
commodities. 


REFRIGERATOR  CARS 


449 


Such  instructions  must,  however,  be  based  on  the  type  of  car 
used.  Far  too  many  cars  now  on  our  lines  would  be  useless  no 
matter   what    treatment    they   received.      For    example,    we    still    have 


(HART  XV. 


cars  with  one-half  inch  of  some  insulator  posing  as  refrigerators,  and 
we  still  have  cars,  the  walls  of  which  contain  only  paper  and  air 
spaces.  Considering  the  relation  of  foodstuffs  to  the  winning  of  this 
war,   I   cannot   look   upon   the   use   of   such   cars   to   transport   perish- 


450 


CORK  INSULATION 


ables   as    anything   short    of   a    wasteful    practice   and    should   be    dis- 
continued. 

Look  at  Chart  XV.     One  of  the  cars  represented  is  of  the  paper 


CHART  XVI. 

variety,  the  other  well  insulated.  There  is  a  variation  of  more  than 
15°  between  the  two  cars.  The  floor  of  the  one  is  often  six  or  more 
degrees  warmer  than  the  ceiling  of  the  other.  The  paper  car  follows 
the  atmospheric  temperature  and  the  refrigerant  in  the  bunkers  is 
almost    powerless.      Yet    again    and    again    this    summer,    eggs,    fruit. 


REFRIGERATOR  CARS  451 

vegetables  and  dressed  poultry  have  been  shipped  in  these  cars  and 
sometimes  they  have  been  loaded  ahnost  to  their  cubical  capacity! 

The  relative  value  of  the  air  space  and  paper  as  an  insulator 
may  be  further  emphasized  by  comparing  a  car  built  with  what  is 
termed,  especially  in  the  south,  "a  double-felt-lined"  car.  Such  a 
car  is  considered  to  be  a  greater  protection  than  a  box  car  but  in 
no  wise  is  it  a  refrigerator.  Indeed,  it  is  not  provided  with  ice 
bunkers.  Chart  XVI  shows  how  the  temperatures  on  the  ceiling  of 
such  a  car  follow  the  atmosphere.  Compare  its  performance  with  that 
of  the  paper  car  on  the  same  chart,  and  I  think  you  will  agree  with 
me  that  there  is  a  decided  similarity  between  the  two. 

Summary 

Summing  up  the  results  of  such  experiments  as  these  we  are  led 
to  the  following  conclusions: 

1.  A  combination  of  basket  bunker,  insulated  bulkhead  and 
floor  rack,  produces  a  circulation  of  air  which  is  not  obtained  in  a 
car  having  a  box  bunker,  open  bulkhead  and  bare  floor  or  permanent 
strips. 

2.  Such  a  basket  bunker  car,  approximately  33  feet  between 
bulkheads,  can  refrigerate  the  top  and  bottom  of  the  load  in  the 
two  middle  quarters  of  the  car,  provided  it  is  sufficiently  well  insu- 
lated and  not  overloaded. 

3.  Cars  which  depend  for  insulation  on  paper  and  air  spaces 
should  not  be  used  for  the  transportation  of  such  perishables  as 
fruit,  delicate  vegetables,  poultry,  eggs  and  fish. 

4.  Cars  having  one  inch  of  insulation  will  not  carry  eggs  suc- 
cessfully during  hot  weather  when  loaded  more  than  three  layers 
high. 

Cars  having  one  and  one-half  inches  of  insulation  in  the  side 
walls  and  two  inches  in  the  roof  and  floor  will  not  carry  eggs  suc- 
cessfully during  hot  weather  when  loaded  more  than  four  layers 
high. 

Cars  having  three  inches  of  insulation  in  the  roof,  two  in  the 
side  walls  and  ends,  and  two  inches  of  cork  in  the  floor  will  carry 
•   eggs  five  cases  high,  but  not   six. 

The  box  bunker  car,  regardless  of  quantity  of  insulation,  does 
not  refrigerate  the  two  middle  quarters  of  the  load  when  it  is  tightly 
stowed.     Even  with  an  open  load  the  performance  is  unsatisfactory. 

5.  The  use  of  salt  with  the  ice  in  a  well  insulated  basket  bunker 
car  will  permit  an  increase  in  the  load  of  from  25  to  40  per  cent. 

6.  While  each  commodity  must  be  studied  separately  in  order 
to  determine  the  maximum  load,  the  principles  of  the  relation  be- 
tween car  efficiency  and  tonnage  of  eggs  as  indicated  in  this  dis- 
cussion can  be  applied  to  perishables  in  general. 


452  CORK  INSULATION 

We  are  continuing,  of  course,  such  work  as  I  have  outlined  to 
you  this  evening;  it  will  be  a  long  study  before  all  of  the  many 
questions  which  have  come  to  your  minds,  and  which  have  come  to 
our  minds,  can  be  answered.  It  is  only  by  co-operation  of  the  rail- 
roads and  the  shippers  that  we  can  come  anywhere  near  solving  the 
many  questions  that  we  will  have  to  answer.  You  railroad  men 
have  abundantly  furnished  the  co-operation,  and  we  of  the  Depart- 
ment  of  Agriculture  feel   ourselves  very   greatly  your  debtors. 

If  we  can  be  of  any  further  service  to  you,  please  call  upon  us. 
We  want  to  be  of  service,  of  course,  that  is  what  the  money  is  ap- 
propriated for,  and  that  is  what  we  are  all  working  for. 


THE  DEVELOPMENT  OF  THE  STANDARD 
REFRIGERATOR  CAR.* 

By  Dr.  M.  E.  Pennington. 

Chief,    Food    Research    Laboratory,    United    States    Department    of    Agriculture, 

Bureau  of   Chemistry,   Philadelphia,   Pa. 

A  short  time  ago  the  Railroad  Administration  issued  a  circular 
the  opening  paragraph  of  which  reads  as  follows:  "In  order  to  in- 
sure the  greatest  possible  degree  of  efficiency  in  refrigeration  and 
conservation  of  food  stuffs,  refrigerator  cars  having  trucks  of  60,000 
pounds  capacity  or  over,  will,  when  receiving  general  repairs  or 
being  rebuilt,  be  made  to  conform  to  the  following  United  States 
Standard  refrigerator  car  requirements."  Then  follow  specific  details 
and  references  to  blue  prints  for  the  construction  of  the  car  in 
general,  its  insulation,  its  ice  boxes  and  the  many  details  which  go 
to  make  up  a  refrigerator  car.  Throughout  one  finds  that  the  rail- 
roads are  instructed  to  build  in  conformity  with  the  "United  States 
standard  refrigerator  car." 

Knowing  the  difficulties  which  attach  to  obtaining  agreement 
among  car  builders,  the  desire  of  the  financiers  of  the  railroads  to 
minimize  the  outlay  for  equipment  and  the  great  variety  of  perish- 
ables to  be  transported,  one  may  well  ask  how  such  an  order  has 
come  about,  and  upon  what  it  is  based. 

Considering  the  fact  that  we  have  in  this  country  more  than  one 
hundred  thousand  refrigerator  cars,  and  that  ultimately  all  will 
probably  conform  to  the  essentials  just  laid  down  by  the  Railroad 
Administration,  it  may  not  be  amiss  to  review  the  circumstances 
which  have  led  to  the  issuance  of  "Mechanical  Department  Circular 
No.  7." 

In   the  latter  part  of  the  '90's  and   early   lOO's   the   difficulties  in 


Reprint  from  the  American  Society  of  Refrigerating  Engineers  Journal,  July, 
1919,  Vol.  6,  No.  1,  presented  at  •the  fourteenth  annual  meeting.  New  York,  Dec, 
2nd.  3nd  and  4th,   1918. 


STANDARD  CAR  453 

the  distribution  of  our  perishables  attracted  an  increasing  amount  of 
attention  because  the  length  of  the  hauls  increased  as  more  distant 
markets  demanded  supplies,  and  the  losses  from  decay  in  transit 
kept  pace  with  the  distance  traveled.  Some  of  the  shippers  applied 
to  the  United  States  Department  of  Agriculture  for  assistance,  among 
them  the  Georgia  peach  growers.  These  growers  were  in  trouble; 
they  could  not  successfully  ship  their  product  to  northern  markets 
because  of  the  losses  from  decay.  So  in  1903  Mr.  G.  Harold  Powell 
and  his  associates  undertook  to  investigate  the  matter.  They  studied 
the  effect  on  ripening  of  cooling  the  fruit  quickly  after  picking  and 
before  loading  in  the  car  as  well  as  the  development  of  decay  in 
transit.  Precooling,  however,  was  not  a  reliable  remedy  because  the 
insulation  of  the  refrigerator  car  of  the  south  was,  and  is,  insufficient 
to  retain  the  chill  imparted  to  the  fruit  and  the  air  circulation  in  the 
cars  was,  and  is,  inadequate  to  transfer  the  refrigeration  from  the  ice 
bunkers  to  the  center  and  top  of  the  load.  This  is  a  handicap  which 
limits  the  distribution  of  the  Georgia  peach  crop  and  from  which  the 
industry  has  never  been  able  to  escape.  So  universal  is  the  failure 
of  the  cars  to  refrigerate  the  top  layers  and  the  middle  of  the  car, 
that  receivers  expect  to  market  the  load  as  at  least  two  grades, 
though  the  pack  may  have  been  uniform  when  shipped.  To  anticipate 
the  story  somewhat,  I  may  say  here  that  when  carloads  of  peaches 
in  adequate  refrigerator  cars  came  into  the  market  during  the  sum- 
mer of  1918,  with  top,  bottom,  middle  and  ends  all  in  like  condition, 
the  astonishment  of  the  trade  was  interesting  to  contemplate.  The 
higher  prices  to  the  shippers,  likewise,  were  gratifying  in  the  ex- 
treme, and  the  railroads  had  no  claims  to  pay. 

From  Georgia  peaches  the  investigators  were  called  to  California 
oranges.  The  industry  was  severely  handicapped  because  of  decay 
in  transit.  Again  the  inadequacies  of  the  refrigerator  cars  were 
apparent.  The  investigations  of  the  temperature  in  cars  in  transcon- 
tinental trips  brought  out  the  differences  in  the  different  parts  of  the 
car  and  their  relation  to  the  excessive  decay  in  the  middle  of  the 
load  and  its  upper  portion.  With  oranges  which  ripen  slowly  after 
picking,  careful  handling  in  orchard  and  packing  house  to  eliminate 
decay  could  go  much  farther  toward  ensuring  preservation  than  with 
quick  ripening  peaches.  It  is  interesting  to  observe,  too,  the  im- 
provements in  insulation  and  general  construction  undergone  by  the 
far  western  refrigerator  cars,  in  response  to  the  definite  information 
furnished  and  the  demands  of  the  great  western  fruit  business.  How- 
ever, these  improvements  were  practically  all  based  on  the  require- 
ments of  citrus  fruits,  which  are,  as  we  now  know,  extremely  easy 
to  refrigerate  if  they  are  well  picked,  graded  and  packed.  The  needs 
of  deciduous  fruits,  poultry,  eggs,  butter,  fish  and  delicate  vegetables 
were   still   little   known   and  uncared   for. 

In  1908  the  Food  Research  Laboratory,  which  had  been  studying 
the  effect  of  long  cold  storage  on  poultry,  extended  the  work  to  the 
handling   of   the   fresh   goods   in    the    packing   houses    and    in    transit. 


454  CORK  INSULATION 

Our  object  was  to  prevent  deterioration,  and  to  that  end  the  best 
packing  house  methods  available  were  sought.  However,  we  soon 
found  that  standardized  methods  at  the  packing  house  did  not  give 
standardized  results  at  the  market;  in  other  words  the  refrigerator 
cars  were  a  variable  factor.  This  was  proven,  not  only  by  the 
chemical  and  bacteriological  analysis  of  the  poultry,  but  by  the  tem- 
perature records  on  the  thermographs  placed  in  various  parts  of  the 
load.  Again  we  found  the  packages  on  the  top  of  the  load  and  those 
in  the  middle  of  the  car  more  or  less  injured  by  lack  of  refrigeration. 
Indeed,  it  was  not  and  is  not  uncommon  to  find  chickens  on  the 
floor  at  the  bunker  hard  frozen,